If you change to another gamemode while inside the view of a mob in spectator mode, your hand moves up and down and you can move it across the screen but you still look and move in the direction of the mob. If you press shift while this is happening, it puts you into the mode you were trying to get into.
Linked issues
blocks 1
is duplicated by 6
relates to 1
Comments 6
Attacking mobs while doing this causes you to be kicked with: http://puu.sh/6DPXs
A Mo you are describing MC-46411
Confirmed, also noticed that when viewing through the eyes of a creeper, whatever direction you were facing when you started spectating (North, South, etc) You will be locked in that view, even if the creeper moves his head.
Confirmed