If you put a command block and spawn a white shulker there is a chance of a white shulker if you place it in a mobspawner

We are unable to diagnose your issue due to the lack of proper debug information. Please review the guidelines before reporting issues.
In case of a game crash, please also attach the crash log from [minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/guides/finding-minecraft-data-folder/].

-- I am a bot. This action was performed automagically!