The MessageStats database recovery model keeps changing after the database maintenance scripts are run from Simple mode to Bulk-logged mode.
The expected behaviour should be that the database should remain as Simple recovery model.
This issue occurs when the two Database Maintenance Scripts run at the same time overlapping each other.
When the database maintenance script is run the script notes the recovery model and then changes the recovery model to bulk-logged and once it finishes then the recovery model is changed back to the original recovery model.
If during the running of the first script the second script begins then the script takes the original recovery model as bulk-logged and hence converts the recovery model back to bulk-logged after the second script runs.
The Reindex script, if possible, should be run daily and scheduled to run when there are no gathering tasks running. If this is not possible, run the Defragment script daily, again after all gathering tasks have been completed, and run the Reindex script once a week.
Both the Defragment and Reindex should not overlap otherwise the MessageStats config database would change from the current recovery model to Bulk-logged