garbled characters restore point name

Good evening. DB 19.10, an old restore point was created with garbled characters. It was possible to restore to that point using the preserved buffer, but it was not possible to delete the restore point. As a result, I manually deleted the flashback logs, and now the database does not open.

ORA-38760: This database instance failed to turn on flashback database.

I created a trace of the control file to check how the restore point is written and not deleted by name through the buffer.

***************************************************************************

RESTORE POINT RECORDS

******************************************************************* (size = 256, compat size = 256, section max = 2048, section in-use = 2,

last-recid= 5, old-recno = 0, last-recno = 0) (extent = 1, blkno = 455, numrecs = 2048)