I mean fire types + Will-O, electric types + Twave and poison types + Toxic all make sense. They aren't immune to the respective type of moves, but the status condition instead.
Ground types on the other hand are immune to all the moves of said typing, but not to the status condition. They can be paralyzed by some moves. I feel like steel should work the same way, as it grants an immunity to the whole respective typing as well.
But I'll trust you, if you say steel grants an immunity to both the moves and the status condition and ground just to the moves. How do you know this, do you have any source? I'm interested in this kind of stuff :)
It's weird how they programmed these two interactions inconsistent. A bit sad as well
Thanks for the quick clarification!