diff --git a/seed/challenges/intermediate-bonfires.json b/seed/challenges/intermediate-bonfires.json
index d237bf6f184..baf02e2500c 100644
--- a/seed/challenges/intermediate-bonfires.json
+++ b/seed/challenges/intermediate-bonfires.json
@@ -66,7 +66,8 @@
         "assert.deepEqual(diff([1, 2, 3, 5], [1, 2, 3, 4, 5]), [4], 'message: <code>[1, 2, 3, 5], [1, 2, 3, 4, 5]</code> should return <code>[4]</code>.');",
         "assert.includeMembers(diff([1, \"calf\", 3, \"piglet\"], [1, \"calf\", 3, 4]), [\"piglet\", 4], 'message: <code>[1, \"calf\", 3, \"piglet\"], [1, \"calf\", 3, 4]</code> should return <code>[\"piglet\", 4]</code>.');",
         "assert.deepEqual(diff([], [\"snuffleupagus\", \"cookie monster\", \"elmo\"]), [\"snuffleupagus\", \"cookie monster\", \"elmo\"], 'message: <code>[], [\"snuffleupagus\", \"cookie monster\", \"elmo\"]</code> should return <code>[\"snuffleupagus\", \"cookie monster\", \"elmo\"]</code>.');",
-        "assert.includeMembers(diff([1, \"calf\", 3, \"piglet\"], [7, \"filly\"]), [1, \"calf\", 3, \"piglet\", 7, \"filly\"], 'message: <code>[1, \"calf\", 3, \"piglet\"], [7, \"filly\"]</code> should return <code>[1, \"calf\", 3, \"piglet\", 7, \"filly\"]</code>.');"
+        "assert.includeMembers(diff([1, \"calf\", 3, \"piglet\"], [7, \"filly\"]), [1, \"calf\", 3, \"piglet\", 7, \"filly\"], 'message: <code>[1, \"calf\", 3, \"piglet\"], [7, \"filly\"]</code> should return <code>[1, \"calf\", 3, \"piglet\", 7, \"filly\"]</code>.');",
+        "assert.deepEqual(diff([1, 2, 3, 3], [1]), [2, 3, 3], 'message: <code>[1, 2, 3, 3], [1]</code> should return <code>[2, 3, 3]</code>.');"
       ],
       "MDNlinks": [
         "Comparison Operators",