A recent change in firewall-cmd --list-all-zones output is breaking the zones reader as the default zone is not read properly and therefore it is considered to be deleted.
coverage: 41.924% (+0.03%) from 41.893% when pulling 50ba1cc13fe2dc6b7dccb8d6f464304fca929bc4 on fix_zones_reader into d1ae32192e055549150ec66ba8b7f5556116377d on SLE-15-SP6.
Problem
A recent change in firewall-cmd --list-all-zones output is breaking the zones reader as the default zone is not read properly and therefore it is considered to be deleted.
Solution
Adapted the firewalld zones reader ignoring anything after the zone name.
Testing