Not sure where to actually report bugs, but in franchise mode, after Ohtani is placed into your pre-set lineup before entering a game as DH, and it's also his turn in the rotation to pitch, using the player lock on Ohtani would have Ohtani both pitching and hitting, except the game doesn't respond to any controls when he's at the plate. This can only be fixed by removing player lock in game or by simulating past his at-bat. Also, subbing out pitcher Ohtani doesn't sub out hitter Ohtani, so Ohtani in the DH spot stays in the game even though he's pulled from the mound. The game properly puts someone else in the DH slot when using quick manage or when the game is simulated, and the bug only appears with player lock, but basically makes playing franchise mode with Ohtani extremely cumbersome while at the same time gives quite a bit of advantage since you can use him as an opener and keep him at DH for the rest of the game.
Also, inability to set an actual 6-man rotation or adjust Ohtani's stamina above 99 in game means that if he's actually played every day like he is in real life he will always run out of energy on the mound around 30 pitches in and start throwing meatballs. Although that's not so much a bug but just a lazy implementation of the fatigue model.