Eh it entirely depends. You make a good point of clarification, but depending on the license and agreement, either company can do it (usually hiring the cheapest third party and just dropping off masters with zero instructions other than make it 4k).

Remastering required boosting all of the shadows to expand and create more pixels. The proper thing to then do is to recolor and bring back the contrast but Warner didn’t bother to do that second part or crop out edges from the original masters

Also define "full theatrical run" because a lot of films only have a couple days.