BTW, I think I discovered a "solution" for my problem, if anyone is interested.
Preamble: PC player. Using custom kb/m settings for infantry and land vehicles. Using Xbox 360 controller for flying.
Problem: When I return to infantry after flying, my key bindings try to reset to default settings. But then try to keep the settings. It is really confusing. Sometimes it mix both. I.e: I use "c" for battle pickup. Sometimes it works well. Sometimes it changes my view. Sometimes it does both at the same time. It is really annoying. I have this problem only if I use the xbox controller and keyboard on the same round, but it maintains for the rest of the game.
Solution (probable): After I return to foot soldier, I do an action as soldier with the controller (shoot) and then, I change to kb/m.