When I just changed the postcount, I ended up with what is labeled post #1, but is actually the 26th post in the thread.
Not a huge deal, but I figure someone else might try the same thing I did and confuse people, and I guess this could be used as a sort of mis-quoting people. Or not. Just a heads-up.
A couple of tries took completely different numbers in the postcount parameter without a problem. Looks like it’s there just to put the number on that post and they didn’t think someone changing it would be a bit problem. As long as the correct post shows up anyway, it’s basically just cosmetic.
Personally, I don’t like that feature because I always want to see the post in context. I prefer using the [post=] tag.
I think it’s more q quirk than a bug. The board uses the “p=XXXXXXX” value to actually identify the single post. The “postcount” value is just for display purposes, you can put 999999 in there if you want, or leave it blank.
It seems that the postcount numbers are dynamic, generated when you open the thread. That avoids gaps in the numbers when you delete a post from the middle of the thread. It also means that when you link to a single post, the board has no idea its actual position in the thread, so that number is passed along in the URL so it can be displayed.