Unable to change VM recovery VRA - getting an Exception: "This is not allowed when you change a datastore."

from the logs:
,E,248,ProtectionGroupController,ChangeRecoveryHostImpl,"Exception occurred during change recovery host implementation: Zerto.Zvm.Common.ProtectionGroupControllerException: VM [VM vm-12345, server 8e285c33-3572-4b0b-9b6d-fecc35d275b8] The recovery compute resource cannot be changed.
This is not allowed when you change a datastore.




   it seems to be related to a previous data store change that was not updated.    




Edit the VPG, but without making any changes.
Click 'Done' and wait until the VPG update has completed.
once done, reattempt the change of recovery host.