[Python] How to diagnose a serial communication crash that happens randomly and very seldom?

I'm connecting to a Lakeshore 336 Temperature controller from Linux Mint via pyserial. My app works relatively well and has operated for months at a time without error. However, it sometimes happen that the device in question stops responding generating the following error message:

device reports readiness to read but returned no data (device disconnected or multiple access on port?)

This error was also happening when I ran an earlier version of this GUI on a RaspberriPi4 thus likely not due to the specifics of the runtime environment.

The API for this device inherits from a custom parent class which implements the read function as shown below. Note that I am using semaphores to try to avoid this issue but it still happens! Can someone suggest a way to diagnose (trigger) and perhaps cure this issue?

def read(self, command):
response = ''
if self.mutex.tryLock(self.waitLock):
try:
if self.ser is not None:
if self.serialDevice:
self.ser.write(bytes(command + self.settings['ending'],'utf-8'))
response = self.ser.readline().decode('utf-8').strip()
else:
self.openSocket()
self.ser.sendall((command+self.settings['ending']).encode())
response, listening = '', True
while listening:
response += self.ser.recv(128).decode()
if self.settings['ending'] in response:
response = response.strip()
listening = False
self.closeSocket()
except Exception as e:
print('While reading {} from {}, SerialDevice:read raised:'.format(command, self.settings['name']), e)
response = ''
finally:
self.mutex.unlock()
#pass
else:
print('{} not locking while attempting {}'.format(self.settings['name'], command))
return response

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