It seems to me that we need to find a requirement for spine files.
The binary is not extracted, maybe the mfa file of the project is corrupted.
The sample you gave me failed to read the binaries when I built it over here.
In the project where I copied the frames from the sample into a new project, the binaries also worked.
(There is no visible difference, so it is a very strange behavior.)
http://ugken.com/ext/Spine/sample2_mfa.zip
I am able to assemble your project properly. But when I transfer from it to the new one, it stops working. It also doesn't work if I transfer my material to your project. It looks like my program or computer can't create a relevant project or material initially. Some of the system configurations allow the utility to work only partially. The situation repeats on different computers and engines. It looks like the reason is at a low level of the system.
I also found that when transferring a scene to another project, the file does not detect itself. We have to hand replace it in the event editor with another one, then back.
Registration in the binary space is a necessary thing.
And although the binary data was to be extracted without an extraction instruction (the extraction instruction is executed inside the Extension)
The extraction function was not working well depending on the environment.
(I believe this has been fixed in the 20231116 version)
Thanks for the report.