A One Identity Manager Database is installed in SQL cluster (High Availability Group).
Frozen jobs are then observed in the Job queue with following error message:
"[System.Data.SqlClient.SqlException] Cannot use SAVE TRANSACTION within a distributed transaction."
In the SQL Cluster setup, check if the option DTC_SUPPORT=PER_DB is enabled.
If the One Identity Manager database is installed in an SQL cluster (High Availability Group) and the option DTC_SUPPORT = PER_DB is set, replication between the server is done by Distributed Transaction. However this will cause the 'Cannot use SAVE TRANSACTION within a distributed transaction.'
This is a known issue (#30972) and also stated in release notes:
Identity Manager 8.1.2 - Release Notes
Disable the option DTC_SUPPORT = PER_DB. More information can be found here: Configure distributed transactions for an Always On availability group.
At the time this KB article is written, there is no hotfix available for issue #30972.