An error may be found in the logs along the lines of:
'integrity constraint (FW.FK_MO_CASE_HISTORY_EVENTS_A01F) violated - parent key not found'
or
'integrity constraint (FW.FK_MO_CASE_HISTORY_EVENTS_8F07) violated - parent key not found;'
This happens where case history is attempting to generate an event for a subgroup ID that does not exist, which occasionally occurs in Mosaic due to issues like a brief loss of connection.
Mosaic easily overcomes this by re-creating the failed subgroup. However, by then, the event against that subgroup has already been recorded. This doesn't result in data loss, as the event will still be re-created against the new subgroup. However, it does create an orphaned record in the Mosaic tables, referring to a non-existent subgroup.
When this happens, a script can be run to identify and remove the problematic data, allowing case history to generate correctly. If you're experiencing this issue, please raise a new case and we'll advise further