Steps to reproduce

when setting a custom startdate in the "Publication date" menu, the date value is set to an "it seems random/wrong" value or a endless loading occurs

for example:
01.07.2026 12:00 -> 20.06.2007 12:00
01.08.2026 12:00 -> 20.06.2008 12:00

the time is not affected, only the date. Seems like it uses the the month-field as an year-field...

Tested with:
General-Timezone in WebUI is set to Europe/Berlin
PHP-Timezone is also set to Europe/Berlin

also tested with both set to "UTC"

checked also: Database SQL field format is "datetime"

we checked another thing: changing the date format in personal setting to something else than dd.mm.yyyy -> will result in an endless loading screen when setting the publication date in the survey.
we changed it back to dd.mm.yyyy, than we have the behavior like described above.

Expected result

date is set to right date

Actual result

date is set to false date