Actually now that I think about it, I may have messed something up when I exported the clip. I'll report back here after I try to reverse that.
EDIT: Nope, that wasn't it. I had Womble set to de-interlace and IVTC, which I thought might have caused the problem, but after I unchecked those options, VDubMod still loaded it as 27secs and not 32.