Oracle BUG DB RU 19.12.0.0.210720 or DB RUR 19.11.1.0.210720

After applying DB RU 19.12.0.0.210720 or DB RUR 19.11.1.0.210720, you may notice that the Block Change Tracking (BCT) file is getting created of a size that is not in line with the database size.
Oracle recommends that you apply interim one-off Patch 33185773 to correct this problem(s) in the RU/RURs indicated above.
Note the fix for this issue has been included in the Oct2021 quarterly RU/RURs.