Alarms page sometimes does not show Stop and Snooze buttons when an alarm happens

In Fedora openQA we have a test of the Clocks app. Among other things, it tests the alarm functionality: it sets the system clock to 9:00am, then around 9:02am it sets an alarm for 9:04am, sits on the Alarms page and waits, and makes sure the alarm shows up.

In some but not all instances of this test since around 2024-10-03, the alarm notification appears, but the Alarms page does not show Stop and Snooze buttons like it should. This is how it should look:

This is how it looks when the bug happens:

When it works as it should, there's a clear transition on the Alarms page when the alarm occurs - the time of the alarm is shown much bigger, and the buttons appear. When the bug happens there's no transition on the Alarms page at all - the notification appears on top of it, but that's all.

As the bug doesn't happen on every run I can't be sure what change triggered this - the first occurrence I can find is in Fedora-Rawhide-20241003.n.0 , but it may have been introduced by an earlier change and just not happen to have been triggered till 20241003.n.0.