I've only experienced this with former employees who were already entered as 'single' from the main employee screen.  If you have a new employee, I only enter as far down as the pay period type.  Don't hit enter.  Then go to the W4 tab and you are able to choose HOH box.  It would have been nice to have some type of instruction with the update, but just glad we finally got the update for the 2020 Form W4 and tax tables.  Now - any word on the update for Form 941 and the GL errors?   I thought there was supposed to be an update yesterday.  😞