TBD. We're bumping up the difficulty from All-Pro to All-Madden as a first step for our third season (we have our 2018 draft this weekend).
I think that pass pressure - specifically the binary nature of how that's handled, there's rarely a "muddy pocket" in Madden on the default All Pro settings - could easily be part of the issue. Madden already penalizes QB accuracy when the passer is under pressure, and indicates that this happened with a UI prompt, so that's a thing that can happen, but I haven't seen it happen very often.