For some reason, the file in this report had its second mix shader socket with
the identifier "Socket.001" instead of the current "Socket_001". The age of
the file roughly corresponds to when we switched to the node declaration
system. I'm not sure why it has `.` instead of `_`, since the old socket template
system also used `_` as the deliminator. I vaguely remember some issue like
this but it's been a while and I can't find anything online.
The fix is to just manually change the socket identifier. The subversion bump
isn't conceptually necessary, it's just to stop the versioning from running
more often than necessary once the file is saved again.
Pull Request: https://projects.blender.org/blender/blender/pulls/132199
f4acdbaf85