Netflix noticably darker through X1 than TV's app

I have a Sony XBR-65X750D 65" and an Xfinity X1 DVR model XG1v4-A.  Like a couple of other users I've seen, I have the problem where Netflix movies and shows appear noticably darker when played through the X1 Netflix app compared to when they're played through the TV's Netflix app.  I know they're both streamed over the internet, so the only real difference is that one way it's directly to the TV's Netflix app, and the other it goes through the X1 platform in some way. 

I've seen a couple of "answers" that said basically either 1) "The video stream is the video stream, and the only thing that affects it is how your TV displays it", or 2) "Just change the picture settings for the particular input you're using for Netflix."  Well if #1 was true, I would think there would be no difference viewing Netflix through the X1 vs the TV app.  Our TV has just one set of picture settings.  As far as we can find, there are not separate settings per input. 

So with this in mind, does anyone--especially Xfinity personnel--have any idea why the same movie or the same episode of the same show would appear noticably darker when played through the X1 Netflix app as opposed to the TV's Netflix app? 

Thanks! 

Scott