If people throw a potion above a lake or a ocean (Not IN the water), the potion particles will be shown like if they are in the water. It happens also with potion particles of the player. It happens with all the potions.
Environment
1st computer: Windows 7 64-bit, Minecraft Launcher 1.6.61, Java 1.8.0_73 2nd computer: Windows 10 64-bit, Minecraft Launcher 1.6.61, Java 1.8.0_25
This issue duplicates MC-9553