If found something to be either a typo or...?
The rules on the virtue Magic Sensitivity states that: "However, your sensitivity makes you more susceptible to magical effects: subtract your Magic Sensitivity score from all magic resistance rolls you make."
Shouldn't this be the Total rather than a roll?
looks like something got missed in the transition to fifth edition. That looks like it should be errata (did you check the errata list?)
Yes, and found no mention of it.
Definitely should be errata.
Hmmm... I must be in a typo-busting mood (or maybe it is because I am making a new magus character, yeah ), and I believe I just found another one in HoH:TL (p 75), where the Odor of Lingering Magic spell with Smell target states Vision in the calculations below.. but I just realised that it is already in the errata.