Calendar History Not Correctly Showing "All day" Attribute

[burgoyne]

It seems like the "All day" attribute is not correct on the calendar, but it is correct on the individual entity. For example, sensor.ical_work_xxxxxxxx_event_0 is an all day event, but when I view the calendar, it was changed to the "on" state, but shows "all day" as false.

I am trying to trigger an automation when the calendar is changed to "on", but my condition is that the "All day" attribute is false. Because of this bug (All day being false all the time), this automation gets triggered even for "all day" meetings, which I don't want.

edit: Is it possible to filter out all day events from ever being pulled in? If I could remove those, it would simplify my use case a lot.