This bug is still active. This thread shows there are 12 posts across two pages but the link to page 2 takes you to page 1 again so you can only see the first 10 posts. I tried Firefox, Chrome and Edge to make sure it wasn't browser specific and they all behave the same. The other effect of this bug is if you aren't logged in the forum won't even show that the topic has two pages (either from the main discussion area page or from within the topic), it just shows the first 10 posts.
There is a work around however; if you open the topic and select threaded mode ('display' menu at the top right of the first post ) then the thread window shows all the posts and allows you to view them.
Another annoying issue I've noticed is some kind of window focus bug when using Chrome. When editing text (e.g. writing a reply) you can normally overwrite a word or sentence by simply selecting it with the mouse pointer and typing. This works as expected in Firefox and Edge but not in Chrome, nothing happens when you type. You can delete text after selecting it with the mouse pointer, but even at that point it won't allow you to type anything. If the text is selected via the keyboard (i.e. using shift and arrow keys) then you can overwrite as normal. This behavior seems specific the this forum, none of other forums I use show this issue.