We have not yet encountered this problem, but would be happy to receive your assets for testing! It would be great if you could send us a zip file containing a minimal project where this problem occurs, and send it to firstname.lastname@example.org.
Thanks for the project files.
The asset in the
json directory (
skater boy.json) is exported with
so this will throw errors upon import in the latest Spine-Unity 3.8 runtimes.
I have re-exported the asset from your included project files from Spine 3.8.54-beta and they were successfulyl imported in both Unity 2017.1 and Unity 2019.2 with the latest Spine Unity 3.8 runtimes.
Can it be that you have been using an old version of Spine 3.8-beta? You can check/change your Spine version via
Spine -> Settings -> Application -> Version.