Game crashes when trying to use "/replaceitem entity @e[type=pillager] slot.weapond.offhand 1 shield" on a pillager

Whenever I tried to use "/replaceitem entity @e[type=pillager] slot.weapond.offhand 1 shield" on a pillager, The game immediately crashed. Is this just me or is this a bug Mojang needs to fix. Please tell me ASAP when it is fixed

Thanks,

SumisuBushido