Is that during the event where you chase Anastasia down the stairs, and then the issue is coming when you go back up the stairs? There was a bug with that previously, if you go to the download folder and get patch 0.55.13 and apply that to your game, it should fix the issue, but you may need to use the debug key item to go back to Elmgar then return to the church. If it's from something else let me know and I can try and figure out the issue.