This failure is not 100% reproducible, but fairly frequent.

Console log:

==============================================================================
ERROR: SCTP echo client/server transfer
------------------------------------------------------------------------------
Traceback (most recent call last):
File "/vpp/test/test_sctp.py", line 75, in test_sctp_transfer
" uri " + uri)
File "/vpp/test/vpp_papi_provider.py", line 191, in cli
r = self.papi.cli_inband(length=len(cli), cmd=cli)
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 106, in _call_
return self._func(**kwargs)
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 397, in f
return self._call_vpp(i, msg, multipart, **kwargs)
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 604, in _call_vpp
msg = self._read()
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 442, in _read
raise IOError(rv, 'vac_read failed')
IOError: [Errno -1] vac_read failed

==============================================================================
ERROR: SCTP echo client/server transfer
------------------------------------------------------------------------------
Traceback (most recent call last):
File "/vpp/test/test_sctp.py", line 43, in tearDown
i.set_table_ip4(0)
File "/vpp/test/vpp_interface.py", line 290, in set_table_ip4
self.sw_if_index, 0, self.ip4_table_id)
File "/vpp/test/vpp_papi_provider.py", line 242, in sw_interface_set_table
'vrf_id': table_id})
File "/vpp/test/vpp_papi_provider.py", line 160, in api
reply = api_fn(**api_args)
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 106, in _call_
return self._func(**kwargs)
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 397, in f
return self._call_vpp(i, msg, multipart, **kwargs)
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 604, in _call_vpp
msg = self._read()
File "build/bdist.linux-aarch64/egg/vpp_papi/vpp_papi.py", line 442, in _read
raise IOError(rv, 'vac_read failed')
IOError: [Errno -1] vac_read failed

All other logs produced by the Test Framework are attached.