I have bikes and mods and all that
Rider lean does work fine in b14. Maybe your just not seeing it due to using the optional fixed view?
check your in game controller input settings and make sure if you are using steam to run MX Bikes you might need to set up your controller with your steam app.
No the leaning is not even doing it in 3rd person and I know my controller is working because when I setup the lean is shows my ability I moving in the settings and I'm using steam Xbox one controller
Thanks for identifying yourself as a drummer. This requires extra explanation. Make sure lean assist is turned off. Try with all assists turned off.