UPDATE: If I scroll to the bottom of the unread page, save the source, and delete all lines that do not contain class="title" I find there are 637 lines.
Which would suggest
there are are 637 topics that I have not read
449/450 is hard-coded someplace
lying to me about the number of unread posts is annoying
and 4) why should I even believe the number 637, the page-load may have just crapped-out silently at some point,
or 5) you’re just f*****g with us.
My money is on the latter (why else would all the comments only be available via javascript???!?).
Have a look at the numbers, though. 450 keeps reappearing, and I found 600+ posts on the actual unread page. I suspect the number display at the bottom of the page is being limited.