With a pillager or piglin that spawned with a crossbow, if you remove their weapon with a command, the crossbow will be visually removed. when attacking, instead doing melee damage, they will still shoot arrows, and will shoot at a faster time than usual. Entities with weapons spawned naturally also have no durability on their weapons and do not break, unlike Java edition. 

Steps to reproduce:

• Choose a hostile mob that spawns naturally with a crossbow.
• on the entity, run this command:

/replacitem entity @e[type={entity)] slot.weapon.mainhand 0 air

• Notice how the entity has had their crossbow removed.
• Enter survival, and make the entity attack you.

What happens:

The entity will still shoot arrows, even without a crossbow.

Expected outcome:

The entity should not shoot arrows without a crossbow, and instead to melee or no damage at all.

If you want to try other things other than air, replace the air at the end of the command with another item.