I am working with FAI (Fully Automated Installation).
After FAI rebooting, the system should do an autorelabeling, in FEDORA 37 it works as well as it should but with FEDORA 38 I get the error " Failed to mount api filesystem".
After changing the bootparameter to enforcing=0 the autorelabeling begins to start correctly.
So I have the question whats the difference between Fedora 37 and Fedora 38.
This appears to potentially be an selinux policy change in that the process doing the autorelabel is not allowed to do so. In the past simply creating a file /.autorelabel was adequate to have the system do a relabel at the next boot, and I believe the command fixfiles created that hidden file.
The actual error you report about the mount failure is a little deeper than my knowledge though.