If you are linked to a topic by someone who has their posts per page (ppp) settings lower than yours and the total amount of posts in the topic is lower than your ppp setting then you will be linked to a topic with no way to see posts before that page.

For example, if you go to this link: https://forums.d2jsp.org/topic.php?t=79765552&f=258&o=5 it links you to post #5 which is page #2 for someone who has their ppp settings set to 5. If you have your ppp setting at 15 or less then you will see the page as normal, but if that setting is 20 or 25 then you will only be able to see posts #5-20 and not have anyway to see posts #1-5 other than deleting &o=5 in the address bar.

If you have your posts per page set to 20 or 25 then none of these have a way to see the posts before the linked page #.
Page 2 for 5 ppp: https://forums.d2jsp.org/topic.php?t=79765552&f=258&o=10
Page 3 for 5 ppp and page 2 for 15 ppp: https://forums.d2jsp.org/topic.php?t=79765552&f=258&o=15

The fix would be to either show all of the posts if the topic has an equal or lower amount of posts than your ppp setting or to show the page navigation buttons at the top to be able to go to post #1.

Bump