Unexpectedly, the "Amazon Echo Skill" app fails to subscribe to any of a device's Alexa-compatible events if the device happens to have an incompatible capability

I have observed some behavior from the Amazon Echo Skill app that defies my expectations: When I choose a device to be included in the Amazon Echo Skill app's "alexaDevices" setting, I expect that, if the device has the "Switch" capability, then, regardless of what other capabilities the device might have, the app will subscribe to the device's "switch" event. However, contrary to my expectation, it seems that if the device has both the "Switch" capability and the "Thermostat" capability, then the Amazon Echo Skill app does not subscribe to the device's "switch" event.

I suspect that I am seeing a particular case of a general rule, namely that, if a device has any capability (for instance: the "Thermostat" capability) which the app regards as being incompatible with Alexa, then the app will not subscribe to any of the device's events, even those events that are part of a capability (for instance: the "Switch" capabaility) that the app regards as being compatible with Alexa.

Here are my questions for the Hubitat developers:

  1. Is the aforementioned behavior the result of an intentional design choice?
  2. If so, what is the reason for this behavior? (I would naively think that, no matter what fancy, Alexa-incompatible capability a device might have, as long as the device supports the "Switch" capability (for instance), the app should treat the device like any other device that has the "Switch" capability.)

P.S. The real-world consequence of the Amazon Echo Skill app neglecting to subscribe to my device's "switch" event is (I think) that, when I say "Alexa, turn on such-and-such", Alexa replies "Sorry, such-and-such is not responding" (even though such-and-such does, in fact, respond as desired).

P.P.S. Here is the driver code I was working with when I noticed the unexpected behavior. I found that, when I commented-out the Thermostat capability and the other Thermostat-related capabilities (the "Thermostat Mode" capability, the "Thermostat Operating State" capability, the "Thermostat Heating Setpoint" capability, etc.), then the Amazon Echo Skill app would subscribe to the device's "switch" event, and Alexa would correctly reply "Ok" when I asked her to "turn on such-and-such".

First of all, the driver need to have capabilities that are unsupported by Hubitat removed. Like Health Check. Second, you do not need to include all of the capabilities you are including. The thermostat capabilities has all of the attributes and commands on the Thermostat Heating Setpoint and Thermostat Cooling Setpoint Capabilities. You don't need to include all 3.