This technical article documents a design change in UIM 20.4 related to the columns shown when in the Group tab -> View Alarms.
Steps to replicate this behaviour:
1. Access the OC -> Select the Groups tab -> Select a Group -> Select the Alarm View button -> Select the 3 dots for further options.
2. The edit columns is not available to modify:
Release : 20.4
Component : UIM OPERATOR CONSOLE - ALARM VIEWER
During support's initial testing, it looked like you could not set it at the group level anymore, it is 1 and done, so 1 group set impacts all groups and your view in alarm manager as well. This is consistent on 20.3 and 20.4. The only difference is that you can no longer set this at the group level in 20.4. Discussing this with engineering they have confirmed this is working as designed:
"Modify the alarm columns at group level is removed from 20.4 onwards.
Now there is a single place to customize the columns is Alarm view. The column modifications in alarm view will persist the change across group view and alarm view."
Support has submitted a request to review all the options in the 3 dots menu which are not relevant for Groups -> Alarms and remove those from the list instead of disable and display.