Controller switches to keyboard/mouse. Settings randomly change all the time

Honestly, what is the fix here? Working so hard to win Division 1, I played about 5-6 games in a row with no issue, then it decides to randomly make the keyboard my input and I have no way of changing it back. I have to forfeit the game and start again, or worse, demoted. Genuinely do not understand how a multibillion company just continues to take the p out of their customers.