No idea, I've never ever seen that before.
Try redownloading ?
(or maybe worst case scenario is your PC is so so so old that it doesn't get the codex used to encode the videos but that's just a random thought and probably not the case.)
171 days ago(+1)
yes, the problem was the exe not using the correct gl version and going back to canvas rendering. If someone has the same problem put --use-angle=gl in the chromium-args inside the package.json.