We’ve asked YouTube for comment.
It wouldn’t be surprising if the move was intentional. YouTube Premium offers background playback as one of its major perks, and it wouldn’t be difficult to use PIP on the web to negate that perk. Still, that could easily be frustrating — it would amount to YouTube taking away functionality that was already present, however briefly.
This also comes as promised YouTube 4K support on Apple TV has yet to materialize. The video giant promised that it’s still coming “soon” through an updated app, but it wasn’t ready alongside tvOS 14 like some had hoped. You’ll have to make do with 1080p for a little while longer.