This makes the most sense.

When I release music through distributors, there’s always an option to enter it into contentid so YouTube can do claims on my behalf. This is all automated and I don’t assume YouTube takes the copyright lifespan into account.

If we extrapolate this to Disney’s use case, they would have had to actively locate it in their contentid entries to YouTube and then remove it that day and hope YouTube refreshes their contentid system timely enough. It’s not very difficult that someone messed up in this chain. So I would honestly give Disney the benefit of the doubt on this one.

Don’t get me wrong, they have an awful relationship with the copyright but let’s make damn sure we criticise them for the right things, otherwise they will only learn that they will get shit on either way and stop thinking about being assholes.