error when calling publish_continue_session

Hi, I am getting an error message when calling hermes.publish_continue_session() from intent call back function with the following configuration: intent_filter parameter set to restrict intent to a single value, and slot_to_fill parameter set to a single slot. Any idea what might cause this behavior?

the error message is listed below:

Traceback (most recent call last):
File “_ctypes/callbacks.c”, line 234, in ‘calling callback function’
File “/home/greg/environments/python3.6/lib/python3.6/site-packages/hermes_python/ffi/wrappers.py”, line 61, in convert_arguments_when_invoking_function
return func(hermes_client, *parsed_args)
File “/home/greg/environments/python3.6/lib/python3.6/site-packages/hermes_python/ffi/wrappers.py”, line 60, in
parsed_args = (handler_argument_type.from_c_repr(arg.contents) for arg in (args))
File “/home/greg/environments/python3.6/lib/python3.6/site-packages/hermes_python/ontology/dialogue/intent.py”, line 68, in from_c_repr
c_asr_token_arrays_length = c_repr.asr_tokens.contents.count
ValueError: NULL pointer access