OpsMan v2.10.38 & v2.9.37 was compiled with stemcell v621.230. The stemcell is untested and not released publicly.
Due to this, the two versions of OpsMan have been removed from https://support.broadcom.com/
If your environment is already updated with OpsMan v2.10.38 or v2.9.37, please upgrade to v2.10.39+.
Alternatively, you can revert back the stemcell using the steps from this KB
You cannot rollback your OpsMan version.