I'm creating a table and I would like the headers to be month-end dates going across. However, once converted to a table and the headers copied across, it no longer recognizes the values as dates and instead copies across nonsensical dates.

The table will be an ongoing spreadsheet where the next month will be copied across and hopefully populates - I've never had this problem before.

Are you not allowed to have dates/formulas in table headers? None of these work

=TODAY()
=EOMONTH("",+1)
=DATE(YEAR(A1),MONTH(A1)+1,DAY(A1))