[skwasjer]

Just to make it clear, the stock props are not centered themselfs, but this is 'offset' by the Local-position parameter. That's why, when scaling the object, the prop starts to wobble. The offset now no longer points to the 'virtual' center.

That's also why both me and Mikhayl have more than once advised to center objects in their own local coordinate space, if they need to rotate around their own center, because you no longer need to worry about difficult animation settings.

There are some scenarios that such behavior is actually wanted/needed, f.ex. with tube doors, where the pivot point (rotation center) is not centered in the middle but near an edge or corner etc...

As I stated above I will try to make a tutorial in the near future about working with animations.