Aqua42

This isn't new behaviour. It has been around for years like this. This is why 2x2 spruce tree farms are directional. The one difference between 1.16 and 1.15 is that the tree is blocked by dirt and related blocks (mycelium, grass, etc). Logs do not block it (tested in vanilla 1.16.3)

I don’t see how that would affect it, try below the ceiling too, they will probably still spawn