Bone rotation glitch

Anyone know why this happens whenever I try to rotate one of the bones on this skeleton? It’s happening with 2 different SKMs, tried reimporting to no avail, all the other SKMs I imported from the same blender project work fine with identical export settings, no modifiers or anything like that.

Never seen this issue before. Could this be caused by a mirror modifier in your 3d software?

No, I didn’t use a mirror modifier in blender, just duplicated the bones/mesh and ran the mirror function, then broke the linked information and reset the transforms. I’m at a complete loss as to what would cause this kind of thing, especially since the other 20+ SKMs I’ve imported with the same settings are working flawlessly.