Hi,

U'm having the same problem since I updated to El Capitan.
To me, the way to reproduce the error is always the same: Open Spine, Load a project, go to fullscreen, do anything (for exemple, try to Translate a node) = Crash, close.

ps.: Sometime it will crash even when not in fullscreen, but I still have to find the way to reproduce this.

The log is attached. Let me know if there's anything else you need.