In the process of animating, I have come to realise that my rig is doing a strange twirl, which isn't desired.
It's very easy to emulate, simply open a new file and set the cube's rotation setting to Quarternion, and then keyframe it at it's base position, and then keyframe it 360 degrees around any axis. When you hit play, it doesn't rotate.
Thanks to FFeller for pointing the idea of intermediate keyframes, which solve the problem on the basic cube, but on my rig, which was generated by rigify, it still applies. It seems eerily similar to a gimbal lock problem, but aren't Quarternions supposed to solve that problem?
As such, how can I solve this problem, as more intermediate keyframes don't seem to work.