Products that go overnight can be overbooked - no check for actual availability

Easy to reproduce. Se the availability to always (Mon-Sun or whole week 00:00 to 00:00). Then set another rule as NOT available on Sunday 00:20 to 14:00.
Set the product duration to 60 minutes and interval to 30 minutes.

The last slot on Saturday is at 23:30 which lasts 60 minutes but there are only 50 minutes from 23:30 to 00:20.

If using addons, you can book even 2 or 3 hours when there is no availability.