Arduino Nano Output D2 lighting up on Modbus msg

[gregorius-ov]

Hey guys, I am not sure if this is the right way to ask about this.

I am using your library in my project to set outputs on my Nano via Modbus. The Nano is setup as a RTUServer and I have configured several registers to set different outputs. It's all working as its supposed to be, except the output on D2. Everytime a Modbus message is received or sent (can't make out if it's just on either send or receive), the output on D2 (my LED) lights up quickly. This only happens when D2 is low, I can see no flickering when D2 is high already. I have found nothing about this in the library nor in the Nano specs and it only lights up when a Modbus message is sent/recvd. The nano handles non-modbus standard messages as well and these do not trigger D2. Any insight into this issue would be greatly appreciated, I would just like to know why this happens.

I've included my code, but please be gentle.

I have tried to not configure D2 as an output but it still lights up.

ArduinoModbus.txt