Mobs automatically spawn on creative (not survival)

On 0.12.1, Mobs are automatically spawned on creative gamemode. They're very useless on creative. Before 0.12.1 Beta 3, Mobs didn't automatically spawn on creative. But After 0.12.1 Beta 4, Mobs automatically spawn on creative!
Please Fix This Bug...

More Informations
Device: Samsung Galaxy S3 3G (Korean) - SHW-M440S

Note: On Picture, I didn't change value of Spawn Mobs automatically. It is default value (bug).