Before Snapshot Action mode is set to 'must succeed' but snapshot proceeds afterwards

I just noticed that when I change the command mode in the UI to s.th. else and back to “must succeed”, the effective policy is shown as “essential”, while before it was blank. Now, “essential” also appears in the output of policy show. And now, it snapshot aborts as expected. So it seems to be a bug in the UI or with the initial state of this policy?