Hm, strange. Investigation in progress!

In the meantime, it's not the best workaround, but you can link directly to the post by taking the url of the first page and putting the post ID at the end, like this: https://subeta.net/forums.php/read/17385/Tarts-CWs-Buttermint-Scrunchies/1#2102177

Just wanted to leave a quick update -

I was able to confirm your suspicion: It's happening because of the age of the thread, and specifically since that post was made in the old forum system.

However I have some ideas on how to fix it, so I'm working on this and hopefully will have a fix soon. :)

Ayyy, I think I fixed it :D :D :D