I disagree. This, at least the lava part of it, is most certainly unintentional. It's not that there's an error preventing it from working that way, it's just they forgot to make it work that way. Endermen are smart enough to teleport away from sources of damage; the most dangerous substance in the game should be no exception.
Of course, flint and steel makes sense, because you don't stop being on fire when you teleport away from what set you on fire.
If it were fixed, it WOULD break a few mob traps, but the smart ones were using piston traps anyway, which would still work.
I've been testing the snapshots for a while and this has been happening ever since the client/server merger. This is especially bad with Golden Apples since you can always eat another one, so it'll make you even if the first one fully restored your hunger.
While a trivial bug, it's still a bug. It could be fixed by making a "recipe" where four smooth sandstone into the crafting table like that gives you nothing. Any other combination would still work.