Ever since rabbits were added, they ignore /gamerule doMobSpawning false. Happens on every world type (except debug).

Reproduce:
1. Open up any world type (except debug)
2. Type /gamerule doMobSpawning false. Make sure the gamerule giveCommandFeedback gamerule is set to true.
3. Type /kill @e[type=!Player] to kill every entity except for the player
4. Keep the game running for 5-10 minutes. You may load new chunks (does not affect), build, and everything normal or AFK.
5. After that time, to test this do /kill @e[type=Rabbit]. If it says "Killed Rabbit" or "That entity cannot be found" one or more times, the bug still exists.