Monthly recurring event is displayed as 1 day longer than its supposed to be (Only Last Sunday in March?)

[juliankehne]

Describe the Bug

As the title says this is a bit of a weird one.

The prerequisites in the event form:

1. Event is recurring monthly
2. In the last week of a month
3. On Sunday

When checking this event in the Web App of integreat the event in March is 1 day longer than it is supposed to be.
See screenshot below or: https://webnext.integreat.app/testumgebung-ical/de/events/last-sunday-monthly

Steps to Reproduce

1. Go to 'Events'
2. Click on 'Create event'
3. Create event with these parameters: Recurring, Monthly, Last Week, Sunday (See screenshot below)
4. Publish event
5. Go to the Web App page
6. Click on the arrow to show more recurring events
7. See that the event in March is a day longer than it is supposed to be

Expected Behavior

All days of a recurring event, no matter what week, month or day, they are on, should have the same event duration.

Actual Behavior

Some instances of a recurring event have different.

Additional Information

Appears to be independent from the year (I only tested for 2025 & 2026 and it was wrong each time for March)
It adds one day to the length, if the base event is 3 days, the event in march is displayed as 4 days.

In Event form:

In Webapp (different event than screenshot above):

Traceback

Related Issues

[david-venhoff]

Theres a good chance that this is an app issue, like digitalfabrik/integreat-app#2901