Curious, I have a inovelli RGBW bulb using the inovelli driver. I don't use much so I'm not a good example of function.
However I just tested it and noticed two things looking at the Events Log:
when I change the color, the resulting events are the color #, a color name then nine more color numbers each within 100 milliseconds of the previous.
When I set color temperature to 4000 then 4011 gets reported. When I set color temperature to 5000 then 5009 gets reported (in the events).
I must admit whenever I see reference to the 'Hubitat Diagnostic Tool' I think of something that we can turn on/invoke to give us more information (diagnostics) to see what is going on and may be causing issues with the hub.
I see this more as 'Things to try to get your hub working' tool.
Just my opinion.
This will assist in his hypothesis that the hot fix caused the hub to lock up. So in this case, I’d call it a tool to help diagnose the problem, wouldn’t you?