Weird 'New Forum Articles' count

I have been noticing this for a while now but was never bothered about it too much. Here it is anyways:

Sometimes the 'New Forum Articles' count is all over the place:


If I refresh the page or open a new article the counts are back to normal:


I am not blocking any cookies and I am not using Ghostery, Adblock or some other extension.

Am I the only one that sees this?