Connecting to panel serial port locks out Installer Code
## Alarm system
Alarm Panel: MG5050, I think it's version 4

## Environment
Running PAI latest in a docker container on Linux.
PAI is connecting to the panel using Serial over IP, via an ESP32.

## Describe the bug
Whenever the ESP32 is connected and pulling data through to PAI, I am unable to access the installer menu. The standard approach of [ENTER] + [installer code] is simply ignored. I do not get the "CODE DENIED" error like I get when entering the _wrong_ code. The keypad simply emits a long beep and then goes back to the home screen.

## To Reproduce
Steps to reproduce the behavior:
1. Fresh panel, after a factory reset.
2. Program some zones and users and things in it.
3. Exit programming menu and witness that it is working fine.
4. Re-enter the programming menu and make some changes.
5. Connect ESP32 to the serial port, and wait for it to boot up.
6. Witness that data is successfully coming through on MQTT
7. Try to re-enter the programming menu by entering the installer code.
8. Despair.

This makes using PAI via an ESP32 _extremely_ risky, as every time I now need to program something on my panel, I must perform a factory reset and program everything from scratch. 

Is this known behavior, or is there possibly something wrong with my setup, and that is putting the panel in some bad state? 