Applying the bypasses_cooldown damage command while the player is damage cooldown by melee attacks removes the knockback.

1. Add damage type, "bypasses_cooldown" or "bypasses_cooldown and no_knockback".
2. These two commands can cause this bug.

damage A 1 [bypasses_cooldown]

damage A 1 [bypasses_cooldown, no_knockback] by B

This bug is not happened by projectile attacks such as bows and tridents.