A couple of things:
*A magus is expected to teach once per year. Not doing so is a breach of the code. This includes if you are not teaching because your apprentice is being fostered;
*So by definition, front-loading the teaching would also be a breach of the code, as would a reorganisation of the teaching schedule. So yes, your plan is a low crime, technically speaking;
*An alternative to wasting your time teaching Latin is to take the apprentice to your covenant, and put him in the care of a scribe or a scholar to teach him pre-apprenticeship, thus delaying opening of the arts and keeping the teaching for more valuable subjects such as the arts. Admitedly, maybe a Tytalus doesn't want a potential apprentice so well treated;
*Even though fosterage is technically a low crime, anyone sueing over it would be on the receiving end of so much negative feedback from his peers, he would probably reconsider sueing at all;
*An apprentice cannot sue the master for poor teaching. His only recourse is looking like a victim yet a potential asset to other magi, who can sue on his behalf, take the apprentice if a Bonisagus, or steal him in a Wizard's War. In other words, the only rights your apprentice has are enforced by other wizards - if they care and dare;
*A magi has the right to kill his own apprentice without prosecution. If a Tytalus learned a quaesitor was inquiring about his teaching schedule, well in advance of a Tribunal, there might be no witness anymore 3 years later, and therefore, no crime. This would make any inquiry into the apprenticeship something swift, or needing discretion;
*The Tytalus are notorious for mistreating their apprentices, and being vindicative is someone gets in the way. If I was a Bonisagus, I would be careful whose Tytalus' apprentice I take, because having someone declare a wizard's war back for no reason, or making a nuisance of himself for the next 50 years in Tribunals is a price I have to be willing to pay, which I might not have to pay by taking the apprentice of another House;
*The Tytalus are also notorious for doing stuff hoping to be sued in order to evolve the Code. They are also the House responsible for the apprentice's poor condition in the first place, having their Book of Apprentice literally written in the peripheral code... if I was a quaesitores, and I learned that, say, a Tytalus had taught his apprentice two seasons in a row every two years for the past fourteen years, I would ask myself whether sueing over a technical low crime is worth risking falling into a Tytalus ambush that is intended to weaken the peripheral code, considering that the apprentice isn't an actual victim here, and that maybe the Tytalus intends for the trial to be a gauntlet, and that's why the apprentice is whispering sweet things in my ear. On the other hand, if I believed the apprentice had not been taught in five years, and demonstrated no knowledge of the arts, that would be an entirely different story.
In other words, your plan is a low crime for sure. Whether anybody does anything depends on a lot of things. Ironically, what is most likely to get a Tytalus to teach his apprentice a season out of every year is not so much respect for the code, as much as knowledge that he's made rivals who would love an excuse to score points against him, especially rivals within the same House.