IndexError: list index out of range when used with jaraco.modb and unpickling an object with references to multiple Queue objects

[dichotomy]

I receive the following error when trying to Unpickle an object that contains references to multiple Queue objects:

Traceback (most recent call last):
File "./jtest.py", line 24, in
tobj2= jaraco.modb.decode(result)
File "/usr/local/lib/python2.7/dist-packages/jaraco.modb-3.1-py2.7.egg/jaraco/modb/init.py", line 66, in decode
return Unpickler().restore(value)
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 76, in restore
File "/usr/local/lib/python2.7/dist-packages/jaraco.modb-3.1-py2.7.egg/jaraco/modb/init.py", line 39, in _restore
restored = super(Unpickler, self)._restore(obj)
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 99, in _restore
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 129, in _restore_object
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 155, in _restore_object_instance
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 164, in _restore_object_instance_variables
File "/usr/local/lib/python2.7/dist-packages/jaraco.modb-3.1-py2.7.egg/jaraco/modb/init.py", line 39, in _restore
restored = super(Unpickler, self)._restore(obj)
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 99, in _restore
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 129, in _restore_object
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 155, in _restore_object_instance
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 164, in _restore_object_instance_variables
File "/usr/local/lib/python2.7/dist-packages/jaraco.modb-3.1-py2.7.egg/jaraco/modb/init.py", line 39, in _restore
restored = super(Unpickler, self)._restore(obj)
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 99, in _restore
File "build/bdist.linux-x86_64/egg/jsonpickle/unpickler.py", line 102, in _restore_id
IndexError: list index out of range

Test code to reproduce:
import Queue

class MyTest(object):

   def __init__(self):
       self.queue_obj1 = Queue.Queue()
       self.queue_obj2 = Queue.Queue()

if name == "main":
import Queue
from pymongo import MongoClient
import jaraco.modb
database = "testing"
client = MongoClient()
db = client[database]
col = db["test"]
tobj = MyTest()
json_obj = jaraco.modb.encode(tobj)
obj_id = col.save(json_obj)
result = col.find_one(obj_id)
tobj2= jaraco.modb.decode(result)
print type(tobj)
print type(tobj2)

The error does not occur when only one Queue object is referenced in the MyTest() class.