My current assessment is that the Diversion module may not be handling custom Reason for Service values correctly.

Test 1 – Used a Standard Lookup Value
I created a Diversion record using a standard Reason for Service lookup option. When I added a Good or Service through the Diversion record, the same Reason for Service value auto-populated into the Good/Service record.
Result: Worked as expected.

Test 2 – Used a Custom Lookup Value
I created a Diversion record using one of our custom Reason for Service values. When I attempted to add a Good or Service through the Diversion record, an incorrect Reason for Service value populated, or no value populated and the field remained blank. I was also unable to complete adding the Good/Service record and received a Failed to Save error message.

I also tested this on the current HIFIS National Demo Site and could reproduce the issue. It doesn’t appear to happen consistently though.