For Mojang's official tracker, see bugs.mojang.com.
Inside Blocks Glitch
Using an ender pearl underground directly beneath glowstone allows the player to see through the map. Console Edition Glitch
Rainbow Biome Glitch
A miscolored Savannah biome in the Pocket Edition. Fixed in 0.9.2.
Bugged Nether Portal
Nether Portals would occasionally bug out and not work.
Sand and Gravel Blocks do not Obey Gravity
Randomly-generated Sand and Gravel Blocks found in the Overworld will occasionally "float" in mid-air, as if they were a block which did not obey Gravity. If the player strikes the block, or breaks an adjacent one, the glitched block of sand or gravel will fall down and obey gravity from that point forward. In situations where several neighboring blocks are glitched in this way, triggering one to obey gravity will cause a chain reaction and all the neighboring glitched blocks will also fall to the ground.