It's a weird issue, I have no idea what causes it. You have my game save from here https://brightrockgames.userecho.com/topics/1166-after-loading-a-save-kasita-changed-color/
Load it and sell a few beast den tiles near the tavern wall, like on my screenshot. There is only one den and only one tavern, you won't miss it. Some walls work correctly, some not. Fortunately, after you build there another room, walls start to work correctly again.
I suspect it's a save/load issue.
Not been able to replicate but maybe possible with your save? I'll chuck it through anyway given it's potentially related to another ticket.
I just encountered this bug in the latest Build (1.5.0b62).
Gamespeed was on 150%.
The foundry was previously owned by the AI and I owned it, sold it.
Hmmm had a look into it but not able to replicate. Will need more information before I can take this on. Especially if you can get it to happen reliably I'll need every bit of info you can provide.