Screen Time blocking apps before the limit is reached

I have a very simple rule setup for my children where “All Apps” are limited to 1 hour on a daily basis, and then they are Blocked. FaceTime is in the “Always Allow” group.

However, after using a mix of FaceTime and some other apps during the day, the TOTAL of which doesn’t even come close to 1 hour, I see the time expired warning.

Why does this happen?

As an example, I took a screenshot of my son’s iPad use. It looks like Screen Time recorded 43 minutes (16+16+11) across individual categories, but the top of the screen shows over 1 hour of use.

Where is this discrepancy coming from? Is that why they get blocked BEFORE the physical use of their apps reaches the configured limit?