Hi @bonordlin - just select the cell with the date (do not click thru to the edit mode) and press delete on your keyboard. This should work. I tested it in my baserow (self-hosted) just now, no problem with deleting the date.
We’ve also created an issue to fix a bug with deleting a date from the date field type using a cursor (as it shouldn’t work this way). Thanks for bringing this to our attention, @bonordlin.