/replaceitem cannot place non-armor items into Armor Stands' head slot

did that ever work then?

Yes, it worked in 15w31a (https://i.imgur.com/MqMsbh6.png) and should be working as per tweets from Searge (https://twitter.com/SeargeDP/status/623125935445921792) and Grum (https://twitter.com/_grum/status/623411853109141504)

did they say you could /replaceitem them? no, they probobly /summon-ed them
doesn't seem logical to me that it worked in 15w31a, could have been a bug on it's own, does it work in 1.8?

Never worked in 1.8.x for items. Replaceitem was broken in 15w31a, so no way to know (ignore my claim above that it did work in 31a, clearly wasn't thinking). Tested summoning with the item and that does work in this snapshot, though it makes no sense to me that summoning with the item works, but replaceitem doesn't.

it does make sense, because /replaceitem takes into accout if it is able to be placed in that slot, and fails if it isn't
/summon ignores that, that's the intended behaviour
images send by mojang often aren't accessable by doing them in the first way you think (banner ontop of head)

o, appearently it now is intended O.o

"/replaceitem takes into accout if it is able to be placed in that slot"

It seems odd to me that all blocks are considered "permitted" items, but not all items, particularly now that items can be properly rendered. I'm not buying it's intended (perhaps out of wishful thinking). Massively cuts the utility of allowing item rendering in the head slot if a new entity has to be summoned every time you want to change the item, or if you have to use entitydata.

EDIT: Glad to see it'll be fixed 😃

Still an issue in 15w31c.

Still affects Armor Stands in 15w32a, though not any other mobs or players.

Now also works properly for ArmorStands and some other mobs