i was trying to watch that yaje part on a tv just the other day too, only to just then notice how badly rendered the footage looked, probably just like you did. i had watched it on my phone before and remembered it looking just fine on that (fine enough for me not to notice anything special about the quality, at least), so i was thrown off.
in this case i think whoever exported the web version of the file probably rushed things and / or used the wrong compression settings (which i reckon doesn't sound likely in the context of transworld standards, yet appears to be the case to me here). i haven't watched riddles in mathematics on dvd yet, but i'm sure (or at least hope) that version would look right.
as far as some other videos may be concerned (i've observed similar quality flaws on the dvd version of a few indie films, most notably on some select clips in them which only enhances my next point) i think the issue has more to do with bad camera settings, vx footage can look like the day and the night depending on how the camera is used, the movement of the camera in itself but the sharpness, color, white balance etc. combo as well. i think filmers used to have more firmly set standards with the vx camera settings before, whilst a lot of people have been experimenting a lot more in that department lately, sometimes all for the better and sometimes it just doesn't work. and again, some others are just lazy on the settings part. see the works of yoan taillandier, colin read / mandible claw, brett nichols / happenstance, jake harris or tightbooth productions (TBPR) for modern instances of crisp, clean vx work