I had a problem where not only were all lights in Hubitat turned off, but also cameras and a water valve. Found this old related thread. The root cause seems to still be true where ogiewon said, "Alexa 'sees' the Hubitat Elevation hub as a Philips Hue Bridge. As a result, everything is most likely detected by Alexa as a LIGHT."
I found that there is a better fix than changing each device in Alexa. I created a "All Lights Group" in Hubitat under Apps - Groups and Scenes, added my lights there, then add the All Lights Group to the Amazon Echo Skill. In Alexa and created a Routine for All Lights Off. This overrides the default behavior described above of turning off everything, light or not.
I'm certainly no expert on Hubitat, so the root cause then is something different. The symptom is the similar as described earlier. Besides all the lights in Hubitat being turned off, the Zigbee devices using the "Generic Zigbee Multi-Endpoint Switch" were also turned off. My fix corrected this behavior. What do you think the root cause is?
The names were "Water valve" and "Rec Room Camera Power". I saw in the log that it also turned off their parent device as a separate action which is "Zig 2-Channel Relay". The parent device is not in Alexa at all, so something told Hubitat to turn it off at the same time.
This is a subset of what was turned off. There are more lights:
dev:2282023-02-16 07:34:56.099 AMinfoHallway Light was turned off [digital] dev:1612023-02-16 07:34:55.779 AMinfoDriveway Lights was turned off dev:1612023-02-16 07:34:55.776 AMdebugparse:zw device: 23, command: 2503, payload: 00 00 00 , isMulticast: false dev:422023-02-16 07:34:55.518 AMinfoStudy Light was turned off [digital] dev:2182023-02-16 07:34:55.432 AMinfoZig 2-Channel Relay was turned off dev:2202023-02-16 07:34:55.427 AMinfoRec Room Camera Power was turned off dev:2192023-02-16 07:34:55.353 AMinfoWater Valve (House Main) was turned off dev:2192023-02-16 07:34:55.353 AMinfoWater Valve (House Main) was turned off dev:1612023-02-16 07:34:54.958 AMinfoDriveway Lights was turned off dev:1612023-02-16 07:34:54.845 AMdebugparse:zw device: 23, command: 2503, payload: 00 , isMulticast: false dev:382023-02-16 07:34:54.804 AMinfoFront Porch Lights is off [digital] dev:1842023-02-16 07:34:54.801 AMinfoPanic Alarm is off dev:2112023-02-16 07:34:54.445 AMinfoChristmas Lights Group switch is off