It share the same export.json with other projects during batch export so I don't think it is a setting issue.
Btw, the error message is confusing, I opened the .bytes file and it doesn't look like a text file at all. Better scan the file 1st before claiming its a text/json file.
P.S. using the latest 4.0 beta runtime.Failed to read 'Kingdom_Pub_Doggo.skel'. Extension is '.skel.bytes' but content looks like a '.json' file.
Did you choose the wrong extension upon export?