Not a blocker, see the impact statement in [1] and the similar UpgradeBlocker drop in [2]. [1]: https://bugzilla.redhat.com/show_bug.cgi?id=1975262#c14 [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1975262#c15
OCP engineering has decided to not ship 4.7.20 due to a blocker. This bug will be shipped as part of next z-stream release 4.7.21 planned on July 27th
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (OpenShift Container Platform 4.7.21 bug fix update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2021:2762
*** Bug 1988175 has been marked as a duplicate of this bug. ***