ical RDATE missing time for additional date

[wohnlice]

Plone=5.2.x
plone.app.event=3.2.14

If you select a time in a recurring event and then add an additional date (RDATE) it sets the time to 0:00 but still assigns a timezone. This leads to this additional date having the wrong time or possibly even the wrong date (because of DST resolution).

Steps to reproduce:

1. Set timezone in Plone to America/New_York. This may not be necessary but it's what I tested with.
2. Create an event on Feb 14 2023 from 10am to 8pm.
3. Add recurrence, repeating 1 time. Add an additional date of Feb 15 (there is no time option here).

The RDATE on export will look like this:

RDATE;TZID=America/New_York:20230215T000000

When importing into Outlook I would expect to see an event for Feb 15 at 10am, but instead it puts it at Feb 15 at 12am. I have seen this put at the previous date on 11pm before in some cases, which I think is because of changes with daylight savings time.

I'm not sure if this is an issue with plone.app.event or with the widget or pattern being used. It looks like internally the rrule value has the time-less RDATE in place and the exporter just respects that, however I was unable to determine where that was happening.