The bug exists in all versions prior to 5.2.2 (5.0.0, 5.0.1, 5.0.2, 5.1.1, 5.1.2, 5.2.0, and 5.2.1). If you can upgrade, would you please report back one way or the other whether or not it fixes your issue?
Are you also collecting stats on your cluster? There is also a serialization bug that impacts your version. I have a theory that the first bug can trigger the second bug. To be clear, I have seen cases of the circuit breaker bug not caused by the serialization bug. I'm only looking for support of my theory.