A cowardly magus never leaves his covenant, and instead sends his brave grog on missions in the dangerous world. On the plus side, the magus has a fixed arcane connection to the grog, and constantly and literally looks over his shoulder, ready to assist him with magic.
The grog travels briefly (a single subjective night) to Arcadia, sensibly avoids all fable points, and keeps talking the whole time to the magus. The grog comes back after half an hour of mundane time (since at 0 fable, 1 day of time in faerie becomes 1 hour of time in the mundane world, see RoP:F). What has the magus seen and heard in that half-hour? A fast-forward movie of the grog? Only a few snatches? Somehow, a full night experienced "normally", but supernaturally "squeezed" into that half-hour?
The grog then travels to a time-dilated covenant; and then to a time-compressed (both Boons from Convenants); and then to a few dreams (via the appropriate Mystery from TMRE, or thanks to a helpful Sahir from tCatC), with time speeds drastically different from those of the mundane world Again, what does the magus experience?
That's a possible solution, even though in some cases it's obviously a house rule that runs again the rule as written (e.g. in dreams).
More crucially, even if adoped, it opens up more questions. In particular, what if there is an "Information providing" link already established between a traveller and a non-traveller? The most obvious is a mental communication power instilled in a familiar bond. But even something like the three cords can "transmit information": a magus with a strong bronze cord can hold his breath longer, and that reveals whether the familiar is still alive, for example. Do you assume the cords stop operating if only one of the two of a magus/familiar pair is in Faerie, a Time Dilated/Contracted site, or a dream?
But how does your grog get and apply Dream Magic or The Greater Dream Grimoire (TMRE p.107f) and enter the dreams of others, for your magus to follow?
If it is the magus who uses Dream Magic and enters his grog's dreams, he is spiritually or physically present there at the time scale of the grog's dream - so does not need to use his AC to the grog for timing, right? So what would be your question?
EDIT: With TMRE p.104 The Road to Lemnos our cowardly magus could indeed send the spirit of his grog into another person's dream without following him. Was that what you really meant, while leaving your readers to figure it out by themselves?
In that case, he could observe his grog's dream through The Path to Lemnos later - but would have just joined him in the dream. Just reading a dreaming grog's mind to follow his dream second by second at the magus's time would be a headache for your troupe to resolve and the magus to make sense of.
Then the arguments of the previous quote still apply - especially about the familiar being alive or not before it exits the Regio. You just cannot know: hence you have Schroedinger's familiar here.
The best solution would be, to not apply the familiar's cords or bond powers while the familiar is not aligned with the magus' time.
I trust my readers to be smart! I also dropped the hint about Sahirs (see the guidelines for Solomonic Travel). Basically, someone opens the path for a grog to enter the dream of ... a troubled princess?
That could be the magus, another magus, a friendly Sahir. I was thinking of the grog entering the dream physically, actually, in that spiritual dream travel is ... trickier.
I agree that the point about arcane connections might have been misleading: that was just meant as an observation that arcane connections by the RAW can connect a dream traveller to the real world even if the dream is flowing at a different timespeed: so your suggestion that any misalignment in timespeed interrupts all magic that can somehow convey information (let's call it OneShot's Bridge, OB) requires changing existing material.
Now, that is not necessarily a "fatal" flaw for OB, which has a beautiful simplicity to it that makes it very appealing. What I dislike with OB is that in some cases information transfer can be hidden "deeply" within a supernatural effect, and in fact added to a pre-existing effect in rather subtle ways, so making information transfer across a timespeed differential cause an interruption is ... in practice much more complicated than it seems.
I think I like the following better, though I agree it still is far from perfect, and I hope someone comes up with a better solution:
Whenever magic is used by two parties to communicate across a time differential, one constant "law" is that events that follow a certain order in one timeflow follow the same order in the other. In general, each party experiences the events happening to the other in "fast-forward" or "slow-motion" fashion, but only rarely does the speed ratio remain constant throughout the communication. Instead, it is much more common for the speed ratio to snap to 1 for the most "mystically important" events (so in those situations the two parties are fully synchronized); and respectively to 0 and to infinity the rest of the time (so the party with less subjective time might only experience a few flashes of the other's two-week boring march through a forest; the party with more subjective time during those same two weeks will perceive the partner as "there", but mostly incommunicado except for a few brief, echoing flashes.
First I think we agree, that Hermetic magic cannot look into the future - that hence truthful information cannot be obtained by magic before its time.
Where I state specific logical necessities - like for Faerie and Twilight Void realms and study at covenant Sites distorting time -, you extend them to be general suggestions.
These you then apply to situations like TMRE p.102ff Dream Magic, which handles the illusory passage of time and events in the dream separated from the waking world (TMRE p.105), and hence requires only precise and somewhat cumbersome storytelling enforced by a specific player.
Another obvious option if you simply want these effects in your saga is to use the guidelines from dreams themselves- which is to say the compressed or extended time information is experienced as if it were a dream which seems to be of the appropriate length but in actuality takes the time which the magus has available. Of course the magus will recover from casting and so forth based on his real time, not "dream time"
It seems to me that the only generalization I made was to include dreamscapes (or rather "reinclude them" from the original post) but otherwise I interpreted your suggestion correctly, right? Any misalignment in timespeed interrupts all magic that can somehow convey information. Because, while I made the argument using familiar cords as an example, the essence of it applies to any magic that can somehow convey information.
And it does not appear to me that dealing with dreamscapes is any different, except that it's one case where your suggestion is explicitly against the RAW.
That's what I actually meant in my original post with "Somehow, a full night experienced "normally", but supernaturally "squeezed" into that half-hour".
This would be the best solution except for the fact that communication is not necessarily between the minds of two parties. For example, you could have an enchantment that creates a visual image of what's happening to the grog in faerie, and that any person passing by can just stop to watch -- think of reality TV.
Then one cannot make the argument "ok, I've seen through my mind's eye the grog for what felt like a whole night, though only half an hour elapsed", because there's no mind's eye, but a "tv show" going on in objective, rather than subjective, time.
You mix up what I wrote about those domains with own times, where events can have direct, lasting consequences for beings present in them - like Faerie, Twilight Void, covenant Sites distorting time - and TMRE p.102ff dreams, where this is not the case for spirit travelers.
(1) For spirit travelers in dreams we have TMRE p.105:
Permanent change may appear possible within the dream ( ... ), but all is lost when the travelers leave the dream and return to the waking world (or when the dreamer wakes).
In other words, the time of the dream is an illusion.
Yes, dreamers can remember their dream later in standard time, and it may influence their decisions. But this is no longer an issue of conflicting times.
So ArM5 rules are very free about time in dreams (p.104):
Time, too, is no longer linear and fixed - a dreamer may skip time, rolling up long periods to pass in an instant, or make a brief moment seem like days (or longer). Travelers who part and reunite in a dream may find that each group has taken a different time to reach the juncture. Almost any change is possible in dreams, and most physical laws can be broken. Also, time in dreams bears little relation to time in the waking world - years may seem to pass in a dream, while only a few moments pass in the real world.
It still allows a magus to read the mind of the grog he sent as a spirit traveler into the dream of another - while what he gets from this mind reading is very much up to the SG.
(2) For beings in another time, whose events can have permanent effects on them even after they leave that time, this is very different:
As Hermetic magic cannot look into the future in its own time A, any information it retrieves about a being in another time B aligns A and B even before that being's return to time A. For a being e. g. in Faerie or the Twilight Void this possibility of continuous synchronization of times by magic directly contradicts RoP:M p.24 and RoP:F p.30.
(3) So you have to distinguish cases carefully. And there are still others. E. g. for physical travel in dreams (TMRE p.107f) the time of the travelers remains aligned to their time outside.
Could you actually quote the passages that are directly contradicted?
Not necessarily, as we read in TMRE, p.107, almost at the end of the page:
"When they return to the real world, usually the time as elapsed for the travelers corresponds to real elapsed time. Sometimes, as with travel to faerie places, the time may be longer or shorter than the real world."
Physical travelers are subject to normal time and movement in their immediate environment, as they are, in fact, awake throughout the whole experience. ...
Dream time does not leap forward around them, ...
... dream logic does not apply to the actual physical travelers, or to physical objects brought into dream. They can resist the arbitrary changes of the dream world.
When they return to the real world, usually the time as elapsed for the travelers corresponds to real elapsed time. Sometimes, as with travel to faerie places, the time may be longer or shorter than in the real world.
So, faerie places is not Twilight Void or Faerie here with time jumps determined by the RoP:F p.30 table or RoP:M p.30 Twilight Comprehension rolls. It refers rather to easily manageable time dilation or compression like in some faerie regios.
If you consider, that a dream in the real world does not even last an hour, this freedom just helps the SG to better tell the dream.
Tracking physical travelers with ACs from outside the time dilated or compressed dream might just look like a fast or slow motion film. I don't see big problems with this.
You get serious problems with tracking constant, consistent time compression via ACs from outside, if you attempt to track research.
The magus outside tracking his faster sodales with an AC might be able to see the blackboard with the "Eureka!" on it and a time lapse view of the elation after a discovery, but will not be able to follow that discovery before lab notes and summaries are written down and handed to him - so he can try to understand them at his own time.
Let me also posit his- everything that comes from a remote experience is in the form imagonem. dreams are entirely imagonem as well, experienced internally. This is why I suggest that such an experience will be dreamlike if experienced directly. If you are projecting an image indirectly first keep in mind that this will not be one of the unbreakable bonds- as such the time compression could cause a form of image skipping for say an enchanted item using an arcane connection that might not happen with a familiar bond.