Cherry-picked commit b0ffed1 from space-wizards/space-station-14/master

Content.Shared/Blocking/BlockingSystem.User.cs

@@ -47,13 +47,23 @@ private void OnUserDamageModified(EntityUid uid, BlockingUserComponent component
             if (args.Damage.GetTotal() <= 0)
                 return;
 
+            // A shield should only block damage it can itself absorb. To determine that we need the Damageable component on it.
+            if (!TryComp<DamageableComponent>(component.BlockingItem, out var dmgComp))
+                return;
+
             var blockFraction = blocking.IsBlocking ? blocking.ActiveBlockFraction : blocking.PassiveBlockFraction;
             blockFraction = Math.Clamp(blockFraction, 0, 1);
             _damageable.TryChangeDamage(component.BlockingItem, blockFraction * args.OriginalDamage);
 
-            args.Damage *= (1 - blockFraction);
+            var modify = new DamageModifierSet();
+            foreach (var key in dmgComp.Damage.DamageDict.Keys)
+            {
+                modify.Coefficients.TryAdd(key, 1 - blockFraction);
+            }
+
+            args.Damage = DamageSpecifier.ApplyModifierSet(args.Damage, modify);
 
-            if (blocking.IsBlocking)
+            if (blocking.IsBlocking && !args.Damage.Equals(args.OriginalDamage))
             {
                 _audio.PlayPvs(blocking.BlockSound, uid);
             }