Sometimes, seemingly at random, the player's left hand will rise above the map and obscure a bit of the bottom left corner of the map. I have observed that this usually happens sometime after entering third-person view (F5) and returning to first person, but this does not always create this result and is not always the cause.

I have attached a screenshot of the problem.

Also pictured in the screenshot, this bug: https://bugs.mojang.com/browse/MC-53184

I'm not sure why the linked bug was removed, but it concerned the disappearing player blips on the map, discussed here: http://minecraft.gamepedia.com/Talk:Map#No_map_blip