FWIW I use Mozilla Firefox and I don't have this issue.
I use DuckDuckgo because it resits clandestine collection of data, when I do a Web search in most cases it refuses Cookies automatically.
Anyway, the problem.
I have just stopped DuckDuckgo from filling in the login details.
Viewing the forum not logged in, everything appears to be normal, of course I can only look.
But when I login, the invitation's to contribute show with any topic in any thread showing the posts in what appears to be a random order.
As mentioned in the thread, I had done the same using MS Edge and got the same issue, once I logged in the posts in threads were out of order?
MS Edge is in fact Chrome just renamed.
I am using MS Win 10 Exec version (64bit) which is fully updated.
It is supposed to be able to run 8, 16, 32, or 64 bit software or it reports it cannot run whatever I am trying.