apollo-client: Getting "Can't find field" errors on null fields (even if the field is nullable)

Since 0.4.16.

Once a mutation comes back and its results are reinjected into the store via updateQueries

Can't find field cursor on result object $ROOT_QUERY.connection({"id":"xxx"}).nodeChildren({"id":"root","limit":40,"cursor":null,"sortBy":null}).
Error
    at new ApolloError (webpack:///./~/apollo-client/lib/src/errors.js?:14:22)
    at eval (webpack:///./~/apollo-client/lib/src/data/writeToStore.js?:59:23)
    at Array.forEach (native)
    at writeSelectionSetToStore (webpack:///./~/apollo-client/lib/src/data/writeToStore.js?:53:29)
    at eval (webpack:///./~/apollo-client/lib/src/data/writeToStore.js?:121:21)
    at Array.forEach (native)
    at writeSelectionSetToStore (webpack:///./~/apollo-client/lib/src/data/writeToStore.js?:53:29)
    at writeFieldToStore (webpack:///./~/apollo-client/lib/src/data/writeToStore.js?:226:9)
    at eval (webpack:///./~/apollo-client/lib/src/data/writeToStore.js?:75:17)
    at Array.forEach (native)