A few people have reported this. One said it worked fine after reloading the last save before heading to the Lady Vengeance. With the one person who emailed support, the problem was in the save itself.
Please email supportdos2@larian.com, with a description (or link to this discussion) and a save on the Lady Vengeance (or a Dropbox or Google drive link, etc) as well as one just before (if available).
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2\PlayerProfiles\<ProfileName>\Savegames' folder. In Windows Explorer you can zip file(s) and folder(s) by right clicking on it/them and selecting 'Send To | Compressed (zipped) Folder'.
