Quicktime interpreting anamorphic DV footage as 872.72x480

Over the past month or so, I noticed small black bars at the top and bottom of all the SD videos I produced. For a while, I just ignored it, but as it keeps happening (and it's begun to happen on some of my co-workers computers), I'm realizing this might actually be a bigger problem.

I've discovered that the issue is that after exporting from FCP, Quicktime interprets the video as being 872.72x480, which is due to the fact that it's conforming it to Production aperture, rather than Clean. I have no idea where the setting for this is stored, nor why it would suddenly switch.

Has anyone else experienced this, and have they figured out a way to fix it without manually adjusting every video?

Up until the past month or so, It exported without any aperture selected, not sure what caused it to change...