After Zurich Upgrade, we are no longer able to manually change approver in RITMs

[Margie2]

We just upgraded to Zurich.  Now, when trying to manually change an approver in Prod, it will not allow.  We did not see this issue in Dev and Test.  Does anyone know how to make it so we can change approvers manually in the RITM?  Thank you!

[AlpUtkuM]

Have you checked the ACLs on sysapproval_approver table?

[Margie2]

We did check, but it is working in Dev and Test but not in Prod.

[Margie2]

We did check ACLs on sysapproval_approver table, but it is working in Dev and Test, just not in Production.

[Andrew34]

I've encountered this same issue after upgrading to Zurich, but I did not test it prior to going live to Prod (re-assigning approvals mid-workflow is not something in our testing schedule). It fails in all three of my instances (Dev/Test/Prod). 
Here is what I used to be able to do: 

1. in an RITM, open the Related List for Approvers and click Add.
2. search & select a new approver.  Keep the original approver as well. Save.

3. the new approver shows as "Not Yest Requested" and the original approver shows as "Requested."
4. set the new approver to "Requested."  Refresh the RITM screen.

5. set the original approver to "No Longer Required."

6. the new approver would receive the email, approve it, and the Workflow would continue (This method does NOT work for new Flow Designer flows, only the older style Workflows)

After Zurich, after I click Save (step 2 above) the new approver does not get added to the approvers list. HOWEVER! When I checked the sysapproval_approver_list I can see all the line items where I've attempted to add the new approver, except the "Approval for" field is (empty).  See screenshot.

RITM1526502 and RITM1526503 are requests where I tried to add a new approver. each multiple times. 

So it looks like it is "trying" to add the new approver, but not adding them to the RITM.