The bug
If you are inside of a block in spectator mode, it considers you to be "looking at" the block you are in. This means that you can't look in containers. This makes it difficult to look in chests in mineshafts or strongholds. This will happen in any game mode, but it's only a bug in spectator mode.
Comments 20
Confirmed for 14w31a, but I am not sure if it I would call it a 'bug'. If you are inside a block, the game considers you to be 'looking at' the block you are inside, and does not register that you are looking at the chest or entity outside of the block. I believe it has always been this way (but it was not of concern before the introduction of Spectator Mode). The F3 screen's "Looking at:" coordinates are evidence of this.
But I do think it would be good if this was changed for spectator mode, to allow clicking through/inside blocks (within reach).
"If you are inside a block, the game considers you to be 'looking at' the block you are inside, and does not register that you are looking at the chest or entity outside of the block." That's the bug. There is no reason that should happen for spectators.
Can you please explain the bug in more detail and what you expect from it to happen. For example if your head is in an air block you can open a container next to you.
I think it does make sense to not be able to interact with entities while inside the block. However in spectator mode you are not exactly 'inside' the block.
Confirmed.