Controller button mapped to android back button

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So, out of nowhere, my controller's "B" button is mapped to the back function of Android. When I push the button, it causes the game to exit. Same thing applies in any other app, it will trigger the back function of android. This is with both a Xbox One S controller and a Gamesir gs3 controller. The only thing I really did was install an older build of Dolphin to fix the entire screen being dark when playing Mario Kart. Before, the controller worked fine, but the game was too dark to see well. Now, the graphics are fine but the controller in Android has gotten screwed up.

[9646gt]

Anyone? I can't seem to find a solution online after searching high and low. I assume there must be a simple setting in Android that I am overlooking?