Do the community pages push you to impervadns?

I'm noticing that only Sophos community pages seem to have a problem where queries get pushed to Of course, I'm trying to not have lots of DNS queries going to random DNS servers, so I block it. (Sophos has its own product for DNS protection, and this is not it.)

This happens with Firefox and once the switch happens, every attempt to refresh a community page tries to hit imprevadns. I have to quit Firefox and relaunch it for things to work normally. So maybe it's a Firefox thing, but no Firefox preferences seem to push DNS in this manner, and it only happens with Sophos Community pages.