Observer updates weirdly in reaction to opening/closing chests

Filled shulker boxes don't drop when /gamerule doTileDrops is false (WAI?)

Cannot drink potions

Conditional Chain Command Block checks block behind it, not last command in chain

Applying the same attribute modifier to multiple slots only affects the last slot

Cannot remove offhand item from armorstand

Items of different data values stack when pulling from the creative inventory

Minecraft 15w33b refuses to download/launch

Corrupt pack.mcmeta causes crash

/setblock does not work with data tags

Item data tags don't work on item entities

Minecraft randomly freezes, then goes to a black screen

Can't /summon WitherSkull or Fireball

Repeaters sometimes pulse repeatedly forever when given a 1-tick pulse.