Thank you for the video you provided, @Quasar108.
Having read your previous posts, I just want to clarify - is this not your first playthrough of the game and its expansions? Have you already played through them before, and taken over the trading posts before, as that's what I understood from you writing:
This is the first time this problem occures to me. I have already liberated every trade posts in previous games.
If so, I'd like to make you aware that we're investigating an issue currently whereby reloading a save after a post has been built, or else playing a new game after claiming the posts in a previous playthrough, can prevent them from being claimed again - even if you acquire the deeds.
We'll keep affected players updated with new information as we receive it, but for now, thank you for any additional information you can provide to us as well! I'll share your video with the developers for them to review as well.