Request as proxy not working anymore

Steps to repro:

1. Log into bugfest environment
2. Create a request
3. Select a requester who is a proxy for another user (you can use cboerema)
4. In the popup, indicate that you want to request on behalf of sponsor
5. Save request

Expected: The sponsor should display as the requester and the patron initially entered (cboerema) should display below as the proxy. Request should not save on its own and, when it is saved, it should continue to display the the sponsor as the requester.

Actual: Everything looks good for a second on the create form but then the request saves automatically and it saves incorrectly (cboerema is listed as the requester)

Additional info:

• c.awenius tested this as part of bugfest on March 25 and it was working at that time. What could have happened to cause it to later fail?
  
• We did make a minor change to the display of this data on the create form during Q1 2020 (UIREQ-413) and I remember testing it myself. I would be surprised if I missed this at that time, but maybe I did?
• Okay, I just tested this in edelweiss and the same thing happened there! https://folio-edelweiss.dev.folio.org/ Looks like the test case for this was pretty weak so testers didn't notice it was failing. I just updated the test case to make it more clear.