Interesting
I think(watching your video) that you have given yourself the solution. You dragged the audio to a stereo track and all went fine, I would continue to do that, then split it out to 2x mono after committing the EA edits. Also, I try to always lock a warp marker at each end of the region as I hate when the audio goes "wild" past my last locked marker(not sure that would have any affect on your issue though).