Root cause is that there are multiple switch services for a given device. Ideally, commands other than on/off would be stateless switches, but stateless switches don't appear to work (see last comment here: https://github.com/KhaosT/HAP-NodeJS/issues/134). Unless HAP supports setting state on a StatelessProgrammableSwitch, only On/Off commands can be used.
Root cause is that there are multiple switch services for a given device. Ideally, commands other than on/off would be stateless switches, but stateless switches don't appear to work (see last comment here: https://github.com/KhaosT/HAP-NodeJS/issues/134). Unless HAP supports setting state on a StatelessProgrammableSwitch, only On/Off commands can be used.