did you configure your controller within steam/steam big picture?
steam → settings → controller
also i have something in mind, that shoulder bash is either a 2 button combo or situational. can’t remember and never used it myself.
quite a while ago this has been reported, and OP assumed it was a problem with remapping LB and RB Shoulder charge not working after controller keys changed - #3 by dardunc
maybe try default buttons?