When an entity has an equipment piece equipped with the "minecraft:damage_absorption" component is hit by a projectile, it will cause the entity to be knocked back.

This occurs even if the "knockback" field within the entity projectile component is set to false. This occurs regardless of the damage type the "minecraft:damage_absorption" is set to absorb.

Once the equipment piece with the "minecraft:damage_absorption" component is broken or removed, the projectiles return to their expected behaviour of causing no knockback on hit.

Projectiles that do not have the "impact_damage" field behave as expected, causing no knockback on impact.