Enemies such as Skulfos walk through tiles that have half tiles. Which means it look really odd.
****Also, I don't know if this is a bug or not, but Lanmolas( I don't know if that is spelled right), aren't they supposed to give you hearts, it doesn't seem like they do anymore. Or maybe that was a bug. XD
For a long time, there has been a similar bug where enemies walk through the top half of a combo whose bottom half is walkable and top half is solid.
That Lanmolas not dropping items has been fixed.
I'm not certain whether enemies walking over half-solid tiles should be considered a bug or not. They do it in the NES game; it's just not that noticeable since there aren't many half-solid tiles. It's always been that way in ZC, in any case.
In regards to the behavior you just mentioned, maybe we should have an NES Fix rule for post 2.5 versions that prevents enemies from walking through half-solid tiles. It wouldn't be a bad idea at all, you know 😉