kaelteschutzgebiet → created an issue.
For everyone who encountered this issue and came here through the issue list or Google: The issue seems to have appeared in Drupal 10 and applies to all date fileds in any RSS view. It should be fixed as of Drupal 10.2.1 as desribed in this core issue: https://www.drupal.org/project/drupal/issues/3383219 🐛 Views RSS Feed Fields adds tag. Active
In the meantime, the fix in #5 in the linked issue resolved it for me.
Just applied this patch. Can confirm that it brings back functionality for me in Drupal 10.1.6.
Thank you!
kaelteschutzgebiet → created an issue.