Last day of month recurring not working

When a recurring event is set to “last day of the month”, the calendar does not show any events after the initial event. There are no PHP or console errors or anything else out of the ordinary and the event works when we switch it to “2nd day of the month” or any other similar setting.

The Problem occurs on this calendar: https://www.xn--huv-bschergrund-3vb.de/buergerhaus/ for the event “Eltern-Kind-Kaffee” on April 26. Clicking on it you can see it is set to repeat on the last Wednesday of every month indefinitely, but only the initial event shows up. How can we get it to show up for subsequent months?

The page I need help with: [log in to see the link]