I've opened up a PR for this: https://github.com/openshift/installer/pull/3217 Feel free to point out anything I am missing.
I've moved the PR here: https://github.com/openshift/terraform-provider-azurerm/pull/1. It will need to be cherry-picked into 4.3.
*** This bug has been marked as a duplicate of bug 1805251 ***
PR: https://github.com/openshift/installer/pull/3314
Closed out previous PR and using PR https://github.com/openshift/installer/pull/3313 with a cherry-pick into release-4.3.
Verify this bug with payload 4.3.0-0.nightly-2020-03-23-130439. Bootstrap resources could be destroyed successfully during installation.
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, 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-2020:0930