I selected a splash potion from the creative inventory and cloned it in my empty hotbar.

What I expected to happen was:
Cloning those potions will not affect anything.

What happened was:
Cloning the potions and switching to survival will cause all cloned potions except the last one to disappear when thrown. Throw the last one before throwing the others will cause all following potions to work properly.

Steps to reproduce:

• Use /gamemode 1 or /gamemode c to go into creative mode
• Empty your hotbar
• Press pick block or normal left key to get a potion from the inventory
• Put it in the first inventory slot (actually, any slot will work).
• Use the pick block key (middle mouse button) to clone this first potion from your hotbar, place it in your second slot
• Do this again and place the third potion in your third slot. Do this as many times as you like
• Go into /gamemode 0 or /gamemode s (survival)
• Try to throw your first potion. It will not be thrown, it will disappear, as will all other cloned potions, except the last one cloned
• If you throw the last cloned potion before the other potions: All following potions will work as intended.

Note: Tested on Instant Damage, Instant Damage II, Fire Resistance Potion and Mundane Splash potion (do /give YOURNAME 373 1 16384 in creative).

Edit: Seems to be an issue on several other items as well.