In some cases, the "Debug Memory Graph" feature in Xcode shows problems ⚠ that have no references -- just a single NSURL or CFString. I can see the allocation backtrace, but I'm not sure what Xcode is trying to tell me about that object -- why is it a problem? Doesn't seem to be a cycle. Is it leaked in some other way? There's no text explaining why that object appears.
e.g.