PySerial readline() first returns command, then the answer

Question

I have programmed a device (Trinket M0 3V) to interface with Python over a virtual COM port. When I test it in a serial monitor it works just fine, but when I switch to PySerial I run into problems. Specifically, I do the following:

import serial
ser = serial.Serial(physicalAddress, timeout = 5)
command = 'bogus\r'.encode()
ser.write(command)
response = ser.readline()

The response that I get is just the command I've written on the line preceding it. However, when I execute ser.readline() again I do get the response that I need. Since everything works fine when I try communicating on my serial monitor it suggests that there's something I'm missing in my use of PySerial, but that's about as far as I'm able to get.

Answer 1

Did you find the infos of https://www.thecodingforums.com/threads/pyserial-unexpected-local-echo.711453/ ?
It had to be linked to the way the echo is handled, and the link gives steps to see if the echo is local or distant, and more...
I didn't find anything about a local echo done by PySerial!
But on the serial monitor (which one?), it seems to be possible to configure it, hence the reason you didn't see it!? ( https://community.platformio.org/t/solved-enable-just-local-echo-in-serial-monitor/539 )