Oh right, I don’t use switch/case … you need to add break; to the end of each case or else they “fall through.” This is why the last one gets to set the message last.
case 'channel1':
output = 'output test 1';
break;
case 'channel2':
output = 'output test 2';
break;
case 'channel3':
output = 'output test 3';
break;