This happens if you have a shitty Wi-Fi. Ours was replaced, but it was found out that it is even worse.
Even with high speed internet it seems to always default to 480p.
It’ll update to 720p or 1080p a few minutes in sometimes. But in general it’s just a large inconvenience.
Low quality saves cost for YouTube and YouTube thinks that you won’t notice the difference between 480p and 1080p on your phone. They don’t fuck with your quality on desktops because they know you’ll notice that
But they do.
For example on desktop if you skip through a video while it’s set to auto (1080p) at some point it will fall down to 480p. Maybe because YouTube thinks your connection has an issue, or maybe they just want to save bandwidth. If you manually set it to 1080p it stays there.
The whole thing is annoying.