Program runs first time, fails on subsequent execution

[n8ur]

I am trying to monitor 4 Arduinos on a Raspberry Pi 3B+ and find that your test program works the first time, but if I exit and run it again, I get no output for some time and then the following error message (the Thread number is not always the same.

Any idea what's going on? And out of curiousity, how does the object know what serial ports are present, and which ones to use? Does it get confused if there are symlinks to the physical port (e.g., "ttyTICC0" is linked to "ttyACM0"?

Thanks!

Exception in thread Thread-7:
Traceback (most recent call last):
File "/usr/lib/python3.7/threading.py", line 917, in _bootstrap_inner
self.run()
File "/usr/lib/python3.7/threading.py", line 865, in run
self._target(*self._args, **self._kwargs)
File "/home/pi/.local/lib/python3.7/site-packages/pyMultiSerial/init.py", line 147, in read_sink
text = i_serial.readline().decode("utf=8")
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xb2 in position 2: invalid start byte