rman incremental level 1 backup ORA-01422: exact fetch returns more than requested number of rows

I have several 19.0 databases.

for one database, using same rman backup command, I always get this error when doing level 1 incremental backup. I stripped it down to the most basic command and still get the error.

I compared show all with a 19.0 db where it works and have configured it the same.

I can touch a file, vi, rm in the /rman/oltp-1/backup/ASTP01 directory.

I don't see this message in relation to rman in oracle support site.

RMAN> run {

allocate channel d0 type disk;

backup incremental level 1 tag BACKUP_L1_DISK filesperset 1 database format '/rman/oltp-1/backup/ASTP01/db_L1_ASTP012_07-07-2021_%U.rman';