AAF & Video Reference 2-pop are not in sync

[defaultowyur855xfyn]

I exported a video reference and an AAF to my sound editor and they're saying that the 2-pop is not in sync. In my Premiere timeline the 2-pop happens right on 59:58 so I don't know why or how they could be off in Pro Tools. I have heard that format/codec makes a difference with this in the export (I had used h.264) but when I tried exporting with ProRes or DNxHD, Premiere keeps showing an error message. Before I waste more time trying to do this, is using one of these other formats really the fix? Also, I know nothing about Pro Tools, but how is it possible that the 2-pop could magically move from 59:58?