I tested a plug-in using the MIDI keyboard node in two DAWs (Reaper and Ableton Live) and I can confirm your issue. Although the node works as expected in standalone mode, within the plug-in it will only respond if the node is set to Omni or channel 1. Even when set to channel 1 the node will respond to MIDI notes on other channels so setting it to 1 is the same as setting it to Omni. I’ll let @taylor know.