This makes me wonder because it seams like something is broken on the system, which could explain any strange behaviour, but if SELinux works at least somehow it should have caused some more lines in the audit2allow output if it was blocking the file access.
But I thing I found it from the earlier output.
The capital S means there is no x behind it, can you please run chmod g+x /etc/icingaweb2/enabledModules to allow the group browsing the directory.