Try this:

 

on the main page in the search box at the top, type (for example): 'neutrino photon'

 

It comes back with the first page of 51 total topics back to the beginning of time. Now click on page 2... it has somehow broadened the search to give you 131 topics, but only for the last year?

Interesting. After I upgrade to the latest version of the forum software (there's an update out to fix various bugs), I'll try this again, and if it still happens, I'll file a bug report with the software makers.

I have upgraded to 3.1.3 and this is still an issue, so I have filed a bug report:

 

http://community.invisionpower.com/tracker/issue-25874-search-result-counting-issue/