1. When a player quits spectate mode, the cursor doesnt come back. This makes interacting with the world extremely hard.

2. When a player attempts to quit specator mode when still inside the view of a mob, the control isnt restored, nor is the special shader in the case of some special mobs.

1) In this case, pressing shift doesnt allow the player to quit the mob perspective either. The only way to quit the current perspective is to go back to spectator mode, press shift, and then switch to another gamemode.

2) Also, the thing that happens after switching gamemode also depends on the gamemode you are switching to. If you switch to creative, fortunately, nothing happens. However, if you switch to survival or adventure, your health, armor, experience, hunger bar, and presumably oxygen bar, go BLACK. This seems to be irreversible, no matter if you quit game or switch gamemodes over and over again. The ONLY way to solve this so far, is to die.

3) If you switch to specator mode, "enter" a mob, go to any other gamemode, and then try to attack the mob you are in, the game will crash, showing this screen (file attached), and clicking the button will bring you to multiplayer title page.