WP changing code in my footer?

Hi all.

I’m running a network of sites on the Genesis Framework using a heavily modified version of the executive theme. Recently we’ve had some problems with one of the tracking pixels in the footer.

Basically what’s happening is, the pixel is entered just before the closing body tag in the footer.php file as it should be, and all looks fine until you “view source” for any page on the site. What’s entered in the footer.php file is there, but has been altered. In this instance, “3D” was entered before the start of every parameter in the pixel. Just to be 100% clear, those “3D'” are NOT part of the pixel and I did not put them there.

Does anyone have any ideas as to why this might happen?