Are you suggesting that it's SUPPOSED to swap your crossbar, but if it doesn't it's a bug? Because it's NEVER done it for me. There is a setting in options to replace hotbar 1 with the petbar when on a pet (I am assuming that's what that bar is called), but it doesn't seem to work with the crossbar.

This game was originally designed for ps4, which requires the use of a controller, so I doubt they oversighted even up to today in not providing some way to be able to do this, I just can't seem to figure out how to.