Thanks for the info here -- I never was able to get it to break in Litmus testing, but we eventually did get it to replicate. Turns out it was some sloppy legacy code that had been copied into the template we were using that caused the problem -- we were referencing a class in our footer that nobody had ever bothered to create a style for.
We've run into this same issue within the past few weeks. We didn't change anything in our templates before it started happening but we've had no luck replicating the issue on our side. Did you ever find a solution for your problem?