As I've stated elsewhere, I have only just begun to acquaint myself with 5th Ed. There are a number of issues which I have with some of the changes made to the way that magic works which would affect the setting. Warping is one of the more pronounced.
One curiosity which I haven't been able to sort out is why Parma Magica doesn't generate Warping Points. It is a persistent, often very potent magical effect which Magi experience from the start of their Apprenticeship throughout their entire lives. It is even more pervasive than a Longevity Ritual, which certain Magi can forego for many decades. By rights, according to the text, Parma Magica should be generating a Warping effect, yet it does not. Why?
The Breakthrough which created Parma Magica shows the way to avoiding Warping almost altogether. No one has followed up on this, but, theoretically, the Parma acts to insulate a Magus or Maga from the cumulative negative effects of magic (i.e. Warping) due to persistent effects.
The Parma Magica isn't actually ON the Magus or Maga, but around him or her. The Parma is a shell, not something which permeates the invoker, thus it doesn't generate Warping because the subject, while generating the effect and protected by it, isn't actually under its direct influence. The logic of this could be sound, and it suggests that many more protective magicks could be employed in this fashion.
Other explanations? Beside the possibility that it's something that went right past the game developers.