If someone uses a backing track that wasn't made by them and uploads it on their UG profile, is that breaching copyright in any way?
Generally, uploading a clip of you playing over a backing track is ok.

there are exceptions (copyrighted backing tracks, singing over instrumental songs etc.) but they're rare.

to answer your specific question we'd have to know where the backing track came from etc.
Rhythm in Jump. Dancing Close to You.

Quote by element4433
Yeah. people, like Lemoninfluence, are hypocrites and should have all their opinions invalidated from here on out.