Idk if its a bug or not

So i was testing the hunger changes in the snapshot today(13:19, time of Montreal) and tipped this: /give MisterMixter minecraft:beef 1 3( because i was thinking its would give a cooked beef) but in staid the game gived me that weird block( the glitch blocks ) that is pink and dark like . And it those again if i tipe /give MisterMixter minecraft:cooked_beef 1 3. I report this bug because i was thinking that the game should say this error messgae : Unknown command. Try /help for a list of commands