[4.12] Index violation on IGMP_Group during upgrade from 4.12.0 to 4.12.1

During an upgrade from 4.12.0 to 4.12.1 a customer has observed crashlooping ovn-master pods with the following error message

$ oc logs -n openshift-ovn-kubernetes ovnkube-master-bx99r -c ovnkube-master --tail=20 -p
:Transaction causes multiple rows in "IGMP_Group" table to have identical values (mrouters, 038b16fa-6aba-4244-9d4f-00a1e2cbf9a2, and []) 
for index on columns "address", "datapath", and "chassis".  First row, with UUID 7e9a18fa-e58c-4547-a7cb-afa934b6cdc9, had the following index values before the trans
action: mrouters, 038b16fa-6aba-4244-9d4f-00a1e2cbf9a2, and d9755997-e909-4d0c-8770-82a902d69a90.  Second row, with UUID 84da3622-3ac7-41f0-a6b5-536a2d5f9137, had the
 following index values before the transaction: mrouters, 038b16fa-6aba-4244-9d4f-00a1e2cbf9a2, and 578d4dd9-cc02-4bcc-8a9c-08dcc3a94190. UUID:{GoUUID:} Rows:[]}] and
 errors []: constraint violation: Transaction causes multiple rows in "IGMP_Group" table to have identical values (mrouters, 038b16fa-6aba-4244-9d4f-00a1e2cbf9a2, and
 []) for index on columns "address", "datapath", and "chassis".  First row, with UUID 7e9a18fa-e58c-4547-a7cb-afa934b6cdc9, had the following index values before the 
transaction: mrouters, 038b16fa-6aba-4244-9d4f-00a1e2cbf9a2, and d9755997-e909-4d0c-8770-82a902d69a90.  Second row, with UUID 84da3622-3ac7-41f0-a6b5-536a2d5f9137, ha
d the following index values before the transaction: mrouters, 038b16fa-6aba-4244-9d4f-00a1e2cbf9a2, and 578d4dd9-cc02-4bcc-8a9c-08dcc3a94190.

4.12.0

Unknown

1. Upgrade from 4.12.0 to 4.12.1
2.
3.

crashlooping ovnkube-master pods

functional ovnkube-master pods

This cluster was upgraded from 4.11 to 4.12.0 then to 4.12.1.
The attached case has a must-gather.