Video Potential VideoPlayer bug, frame / time goes out of sync with texture with url

It seems that the frame and time properties of the video player goes out of sync with the actual available frame when the video player is set to url and the video resolution is too high (beyond 1080p).

In my situation, I'm using the YouTube plugin, which seems to configure a url that serves a youtube video statically. That url is forward to unitys own VideoPlayer. So it doesn't seem to be a bug of the plugin, but of Unity.

I would have thought that if the VideoPlayer has trouble buffering, the time/frame would slow down to be accurate.

Note that I'm unity 2018.3.12f / 2018.2.18f
Editt: I've checked it on unity 2019.1.11f, same issue. the time / frame moves beyond the actual available frame
Another Update: I've tried frameReady, and its the same problem. While it fires when a new frame is rendered, the frame index is way off ahead