Haha, I've got the knack! Post would be too big if I mentioned the things I dislike. Huge drop for Shape Of You though there with Castle not dropping at all; I thought they'd keep roughly the same trajectory.
I know that the data is mainly automated through a database and there might be some degree of auto correct to it. So some random radio play of a song all those weeks back must have been similar enough in the records that aircheck thinks it's the same song
It's a bit like when songs have had last.fm pages for years before existing, though admittedly I find it bizarre that it happens here. It's definitely happening though because Passionfruit has one play too many in life spins when it entered, despite the title not even being known until it was released