Not Sure if Intentional... but Cinderhulk Doesn't Kill Blue Buff

I noticed when playing as today that the for sure doesn't kill blue buff with it's immolate passive (and probably other large monsters); it only reduces it down to 1 hp.

I can see where this would be intentional since you wouldn't want a lucky baron or dragon steal for just walking past it, but I haven't been able to find any documentation of it.

As far as I could tell I was able to kill all other smaller monsters with this passive.

P.S. I'm also convinced my poison from Gromp didn't reduce blue below 1 hp, but I'm not 100% sure on that.