Yes that seems something in the python code: also when connecting from non-Bela Pd I get the same outcome:
('connection addr: ', ('192.168.7.1', 64514))
Traceback (most recent call last):
File "netreceive.py", line 15, in <module>
data = s.recv(BUFFER_SIZE)
socket.error: [Errno 107] Transport endpoint is not connected
In case that helps, here's some debugging info I got from libpd:
Error during recv(15, 0xb5c7a5a8, 16383, 0): Connection reset by peer (error 104)
Error during send(15, 0xb5c7a5a8 7, 0) : Broken pipe (error 32)