This can happen when using keyPaths to traverse an object graph and is hard to anticipate when
defining mappings. RestKit will now perform a sanity check before recursively performing
relationship object mapping operation and will log a warning if the relationship targets
a collection containing another collection. At the debug logging level, RestKit will log
The fix for such scenarios is to use KVC collection operators (such as @unionOfObjects,
@unionOfArrays, etc.) to flatten the collection out into a collection of dictionaries.
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