Marlin experimental I2C bus

Hi,
I'm trying to use the experimental I2C bus function in Marlin 2.1.x but I can't get it to work.

I've simply enabled it in Configuration_adv.h and set the address. Then I've connected it to an Arduino Nano running the example master_reader sketch to read the data from my Marlin board (Ramps 1.4) send over the I2C. So far so good, but when I've send message "Marlin" (M260 A99 M260 B77 M260 B97 M260 B114 M260 B108 M260 B105 M260 B110 M260 S1) from the Marlin board via serial monitor the message received by the Nano was "Hello World!". I'm not sure why that is, I've looked into the file twibus.cpp and found the "Hello World!" message in i2c_on_request() function.

Do I have to modify this function to get it to work or did I overlooked something.

void i2c_on_request() {          // just send dummy data for now
    i2c.reply("Hello World!\n");
  }

marlin as a salve i2c device has not been finished, thus the EXPERIMENTAL_I2CBUS part...