wolfshards I'm sorry but we can't fix it for you. I have no idea why it happens. It is probably a bug in the extension - in that case, all we can do is to let the author(s) know about it. But AFAIK, they are already aware.
What you can do is compare the setup between these two forums and see what's different. Perhaps we can find what exactly causes the issue then...?
Also, on behalf of FreeFlarum, we would like to wish everyone a very merry Christmas and happy New Year! Spend the holidays with people that you love and care about. But please, remember to stay safe and healthy - it means a lot these days โค๏ธ. Let's hope the next year is going to be better than the previous ones