On my phorum installation, we have started to experience seemingly random topics with multiple pages not including the paging within the topic, that is, on the read.tpl page. Instead of being able to advance from one page to the next while reading, we have to go back to the message list.tpl as the paging is still seen next to the subject line there.
I am running 5.2.18
Can you give a link to a thread in your Phorum where this problem occurs?
My attempts to get in contact with dismalbliss were without success.
I'm not able to reproduce the problem.