[Zope] Transience read conflicts

We are seeing occasional read conflicts in Transcience. Traceback (innermost last): [...]] Module Products.PythonScripts.PythonScript, line 323, in _exec Module None, line 6, in setSessionVariable - <PythonScript at /setSessionVariable used for /questionbanks/questionbank_edit/queries> - Line 6 AssertionError: Assignment to "currentQuestionBank" failed database read conflict error (oid 0x1205, class Products.Transience.TransientObject.TransientObject) Zope 2.7.3 Pythn 2.3 Transcience apparently throws an exception rather than serialize. Is that a bug? Is this a bug?