Lets take this post as an example: https://forum-en.gw2archive.eu/forum/game/bltc/Who-sets-Gem-prices/490752
It is on page 4 of the thread. But when you click the link you will be redirected to page 5:
https://forum-en.gw2archive.eu/forum/game/bltc/Who-sets-Gem-prices/page/5#post490752
Currently page 5 doesn’t exist, which causes some problems. But when page 5 does exist, then the link will load up page 5 despite the post being on page 4. So much for direct links to a post.