UpdatableIndexSetting' JSON isomorphism test failure

[bitemyapp]

instance Arbitrary UpdatableIndexSetting' where
  arbitrary = do
    settings <- arbitrary
    return $ UpdatableIndexSetting' $ case settings of
      RoutingAllocationInclude xs ->
        RoutingAllocationInclude (dropDuplicateAttrNames xs)
      RoutingAllocationExclude xs ->
        RoutingAllocationExclude (dropDuplicateAttrNames xs)
      RoutingAllocationRequire xs ->
        RoutingAllocationRequire (dropDuplicateAttrNames xs)
      x -> x
    where
      dropDuplicateAttrNames =
        NE.fromList . L.nubBy sameAttrName . NE.toList
      sameAttrName a b =
        nodeAttrFilterName a == nodeAttrFilterName b
  shrink (UpdatableIndexSetting' x) = map UpdatableIndexSetting' (shrink x)

Currently failing in master. Any suggestions? @MichaelXavier

[MichaelXavier]

What does the failure say? Most of the time JSON isomorphisms fail due to either invariants that don't get enforced at the type level (e.g. duplicate keys) or type ambiguities, e.g. Maybe [a] where Nothing and [] get represented the same in the JSON.