Stem doesn't recognize the CONTROLLER purpose

Hi Ravi. I don't have a consistent repro but several dozen times now I've seen the following when running our integ tests...

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                    test.integ.control.controller                     
======================================================================

test_authenticate                                            [SUCCESS]
test_enable_feature                                          [SUCCESS]
test_extendcircuit (requires online target)                  [SKIPPED]
test_from_port                                               [SUCCESS]
test_from_socket_file                                        [SUCCESS]
test_get_network_status                                      [SUCCESS]
test_get_network_statuses                                    [SUCCESS]
test_get_server_descriptor                                   [SUCCESS]
test_get_server_descriptors                                  [SUCCESS]
test_get_version                                             [SUCCESS]
test_getconf                                                 [SUCCESS]
test_getinfo                                                 [SUCCESS]
test_loadconf                                                [SUCCESS]
test_mapaddress (requires online target)                     [SKIPPED]
test_protocolinfo                                            [SUCCESS]
test_repurpose_circuit                                       [FAILURE]
test_saveconf                                                [SUCCESS]
test_set_conf                                                [SUCCESS]
test_signal                                                  [SUCCESS]

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ERROR: test_repurpose_circuit
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Traceback:
  File "/home/atagar/Desktop/stem/test/integ/control/controller.py", line 401, in test_repurpose_circuit
    controller.repurpose_circuit(circ_id, purpose)
  File "/home/atagar/Desktop/stem/stem/control.py", line 1216, in repurpose_circuit
    raise stem.socket.InvalidRequest(response.code, response.message)
InvalidRequest: Unknown purpose "purpose=CONTROLLER"

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Ran 19 tests in 9.026s

Mind checking to see if we're missing a response that the spec allows for, or if this is a miss with the spec?