Zooming in 200% clearly isn't useful to judge quality...
Normally you would only judge quality with your Magnification factor set to 100%. 200% may be OK to use on a high resolution display if you check the options for Magnification and Fit up to 200% is shown. This is the case with my MBPro R so something else is going on.
In the top screenshot you are looking at the footage panel and judging a movie with the zoom factor set to 100%. I'm assuming that the footage is scaled down in the comp named 57.
In the bottom screenshot we have no idea at all what you are doing ti layer 4 (Comp 57). Assuming that the layer selected in the timeline is showing the movie scaled to 38% and but the Footage panel not showing the result of that scaling I don't know what the nested comp (Comp 57) looks like. I'm assuming the footage that is scaled is less than half the size it is in the Footage panel. In the Main Comp layer 4 (57) is parented to layer 3 (Scaler 1) and layer 4 does not have collapse transformations turned on. Because I don't know what's going on because none of the modified properties of the layers involved are revealed I can only assume that you have a nested comp that contains footage that has been scaled down to 38% and you have scaled that nested comp up using layer 3 to something more than 100%. Because collapse transformations is not turned on the result is exactly what I would expect. If turning on collapse transformations does not fix the problem then my assumptions are wrong.
To trouble shoot a problem you want to select the layers that are giving you problems, press the U key twice to reveal all modified properties an then start digging.