Inconsistent volume on export

My audio volumes are fine in my project but when I export, it seems like the volumes are all over the place. Some tracks have become louder than others and there is an ADR track in particular which is playing back twice as loud as everything else, even though the gain has been adjusted in PP. It's not even that everything is just too loud or too quiet, it's like all my individual volume/gain adjustments haven't exported properly. It's not a playback method issue - I've tried on different computers, speakers, headphones etc.

It's driving me crazy and I don't know what I'm doing wrong. I've tried a few different export settings and nothing seems to be working although I'm not familiar with all of them so could be missing something. I'm aiming for best quality possible. I have Premiere Pro 2018.