I am bumping this thread, because I have this issue with the February 2021 update. I started a game in the old patch, but after upgrading to the February 2021 patch, I need to select a policy but all options are greyed out. Thus I am stuck at the end of the turn. See attached save. I verified the game's files with steam and all is fine.
Edit: My workaround was to switch back to the previous patch by using "ineedlegacyaccess" as a beta access code. I had use an old save from the previous patch, though