See this post:  https://github.com/mrdoob/three.js/issues/13288

It turns out the issues I’ve been having with animations are not in my head and are not isolated to me.  I’ll need to wait until r94 comes out before it’s fixed, but I can handle that.  When doing calculations on skinned meshes that are very far from the origin the numbers get very big and apparently very inaccurate.  Someone much smarter than me with the handle “denbo-ft” suggested to someone much, much smarter than me who goes by “mrdoob” that skinning computations should be done in local space, then the final product translated in world space.  Mrdoob liked the suggestion and it looks like it’s on the road map for r94.  My animations may look weird until that time but hopefully when r94 is release around June 13 everything will look better.  If not, I at least know what the problem is and could theoretically change the way I’m going things to avoid this if necessary.