Sorry to bump this up but after using the program much more extensively I have found that this issue seems to mainly, if not only, occur after a 3-D model has been resized after importing it into the project. If I import a 3D model and do not change the size in any way, I don't seem to have the issue when I proceed to animate. However, if I change the scale or the size of the model on any axis the issue occurs. But I should add it often is only an issue when rotating on a specific axis, and it seems to be inconsistent which axis is affected. I think this resize issue may also apply to the nodes themselves but I can't say with certainty, only from vague recollection of playing around with node sizes.
Apologies if this had already been worked out, but just wanted to add more of my experience :)