I know I'm late to the party but still I'd like to say that I also just experienced that. The opening door shoves him aside, and he's stuck and no longer moves, which causes the door to immediately close when it opens again. However, you can get through and talk to Simons and Manderley so that your task completes. But Anna Navarre can't enter the room on her own... I managed to quickly reopen the door multiple times for her until she got through and could have her conversation with Manderley. Because I'm such a gentleman and I heard she likes me...