Noticed a bug in version 4.0.19
It was supposedly fixed in version 4.0.20, but no.
What's wrong:
There are many skeletons in the project (several dozen), turn on visibility for several skeletons (two or three are enough)
choose to export to GIF, enable the option: "render each visible skeleton separately"
after clicking the Export button, all skeletons start to be rendered starting from the end of the list in the tree, all skeletons, even those that are hidden / disabled!
Not good, this error prevents you from creating a single file consisting of several interconnected skeletons.
EsotericSoftware/spine-editor601