Unified Auditing and ora-00054 errors

Hi All, recently implemented unified auditing and on a couple of databases we receive the following errors:

kzan_run_ddl: OCIStmtExecute

Exception in kzan_run_ddl, 54:ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

ORA-06512: at "SYS.DBMS_PDB", line 33

ORA-06512: at "SYS.DBMS_PDB_EXEC_SQL", line 4

Exception in kzan_cleanup_uniaud_part, 54Exception in kzam_ang_cleanup, 54:ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

ORA-06512: at "SYS.DBMS_PDB", line 33

ORA-06512: at "SYS.DBMS_PDB_EXEC_SQL", line 4

Or we receive:

kzan_run_ddl: OCIStmtPrepare

Exception in kzan_run_ddl, 54:ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired