my right back pedal (used for an extra b button) suddenly switched to rb.

hello! ive been having trouble with the right back pedal on my controller. before i explain some more, this isnt a old controller, its actually quite new. i bought it less then a month ago. anyway, out of nowhere, i quickly noticed that the back pedal wasn't the b button, instead it was the rb button. my rb button hasn't changed, its still just the rb button. my other controller with back pedals isnt having troubles though, the pedals are still the same. i have no idea what happened, ive been trying to fix it the past day and nothing has worked. the pedals aren't just not working on one app or game, its on every app and game.

:)