Last Supper Sept Tickets

Tickets for Leonardo’s Last Supper went up today so I woke up at 4am to try to get my tickets. I got in right when they became available and every day was available except September 6th and 8th. Those dates weren’t even showing as available to book. Not showing like they were sold out. The 8th was the only day I could go. I check single tickets and tour tickets and both show that way. Did I miss something and they are closed on those days specifically?