I am not sure what is happening here exactly, but in the screen recording I show the positions of a character's hand bones around frame 60, move to frame 160 and click to key bone translation, and then go back to frame 60 to show the bones all moved out of place. This is happening consistently and I cannot find a way to work around this. It also only happens when keying translation, not for scale, sheer, or rotate. I am using Spine Pro 4.0.03 and unfortunately under NDA and cannot share the file so I hope the screen recording is enough because there is nothing else that I am doing between these motions. Thank you for your time!
https://gyazo.com/a05556b07c901ee2400a4f7f62bb86b0
Edit: Correction, it also occurs when keying for deformation.