I'm sorry, but my log file was overwritten. However I did record a video of the issue (it is unlisted so I've provided a link). So this has happen to me before, while working with meshes, I selected two meshes while holding down ctrl. When this happens, it flips the image on it's y-axis. Undo doesn't fix the issue. If I scub the timeline or play the timeline while this has happen (with autokey on), it creates new keys at every frame the timeline touches the frames can be deleted; but if it's saved and closed, you will have to redo-this over again.
Specs:
Intuos4 XL
Windows 10(64-bit)
16 gb ram
Radeon R7 graphics card
Spine (Version: 3.4.02)