I added the Diode to the Doorbell2.
Doorbell2 works fine without any issues.
I connected the Doorbell2 to my existing M&S Intercom wires.
Now, my Intercom is constantly chiming as though someone is pressing the button constantly.
When I press the button, the doorbell2 works fine with no issues, however, I have this constant chime in my house from the M&S Intercom.
What am I doing wrong?