toeto Thank you for providing a Spine project that can reproduce the problem! I have found this to be an easily reproducible bug, and have created an issue ticket for this: EsotericSoftware/spine-editor776
The details of the conditions under which this problem occurs are described there. However, since the problem occurs in such a common use case, it would be difficult to work around.
We are sorry for the inconvenience, but I hope you can wait until we have completed the fix.
