Actually I do see the issue in your second image. When you click off it instantly turns grey with the hourglass. When you click on the only instant feedback is the hourglass, it does not change yellow until the device responds that it is on. @vadimchp is using some custom icons with a longer ramp rate, and the hourglass does not show, making it much more confusing in their setup.
I also tested it myself here: Dimmer ON/OFF feedback delay - #18 by jtp10181 I got the same result as you did, which is, I was able to reproduce it. I set the ramp rate higher for the test so the issue is very clear in my image.
