@Kdo - can you install a 4.6 nightly, and try to ssh to one of the master vm's as the "core" user? If it works, please mark this as verified.
Verified that this was fixed in the latest nightly.
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 4.6 GA Images), 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-2020:4196