python-socketio: engineio bug when sending base64 image as data in message?

2018-06-06 15:09:36,096 - AUTO - ERROR - message handler error
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/engineio/server.py", line 408, in _trigger_event
    return self.handlers[event](*args)
  File "/usr/local/lib/python3.5/dist-packages/socketio/server.py", line 516, in _handle_eio_message
    pkt = packet.Packet(encoded_packet=data)
  File "/usr/local/lib/python3.5/dist-packages/socketio/packet.py", line 43, in __init__
    self.attachment_count = self.decode(encoded_packet)
  File "/usr/local/lib/python3.5/dist-packages/socketio/packet.py", line 113, in decode
    self.data = self.json.loads(ep)
  File "/usr/lib/python3.5/json/__init__.py", line 319, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.5/json/decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.5/json/decoder.py", line 355, in raw_decode
    obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Unterminated string starting at: line 1 column 32107 (char 32106)

Any help appreciated. Thanks!