OpenShift Registry using S3 storage returns "invalid memory address or nil pointer dereference" error when it is tried to be hard-pruned

Issue

• The following error message shows up when the built-in OpenShift Container Platform Registry is using an S3 storage backend and is tried to be hard-pruned:

/usr/bin/dockerregistry -prune=check
INFO[0000] start prune (dry-run mode)                    distribution_version=v2.7.1+unknown go.version=go1.16.6 openshift_version=4.8.0-202110121407.p0.git.55dda00.assembly.stream-55dda00
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xde4b1d]