These are known bugs for Oracle Recovery Manager (RMAN) in Oracle Database 12c Release 2 (12.2).
Bug 24309579
When there is a REFRESH PDB, the RMAN recovery catalog cannot be used. If you attempt to use the RMAN recovery catalog, you get an internal error during resynchronization.
Workaround:
Do not use the RMAN recovery catalog. Specify nocatalog.