Path Filter getting replaced with ssl/"wrong" domain?

Hi folks,

I'm guessing that this issue isn't necessarily related to Path Filter *directly*, but I'm completely stumped and I don't know where to begin. I figured since the workaround I've been using implicates Path Filter I'd start here.

On *some* links, when we use "internal:" on our site, it replaces them with a URL that is an older domain, and SSL ta boot. For example, where we expect "http://www.realdomain.com/node/1234," we instead get "https://www.resolvesbutolddomain.com/node/1234." This wouldn't really be that big of a deal, as at least users would get to the right pages (as I indicate in the example, the domains still resolve to the same site, although we'd rather use the newer one), but for the https at the beginning: we don't have an SSL certificate set up for this site, and aren't really planning on it. Maybe that'd solve the issue, but it'd probably introduce others, and fundamentally, the question is: why is this even happening?

Does this sound familiar at all? I feel like maybe this has to do with something pretty arcane in the PHP or Apache config, but I don't really know how to trace this through--any ideas?

Thank you!

DD