Turn on logging for the one that doesn't work, and post a screenshot of the logs here. Also, look at the App Status page (gear icon, upper right of the app page), and take a screenshot of the Event Subscriptions section, post it here.
Yes I can and the device page updates immediately. I also have the simple rule to notify me when the switch is off and that fires every time as does the rule in Rule 4.1 that says if the power reports <10.0 to turn the switch off
OK, so the Basic Rule logs that it turned the switch off. Please look at the device events for that time (Events button on top of the device page), and see if there was an event at that time or not.
Below, you can see where I turned on "a color bulb', then ran the rule. It turned off at 5:33:49,313 and the app's logs shows turning it off at 5:33:49.280.
I tried the same rule except using an Iris V2 ZigBee plug and the rule fired as expected. So the question becomes why is the Kasa plug failing this rule while being controllable from the device page and works in another simple rule and in Rule 4.1?
You've pretty well established that it isn't the Basic Rule that is the source of your problem.
I would suggest that you examine the device events for clues. You mention the device has to be polled. Could that have something to do with it? I suggest you take this up with whoever wrote the driver for it. Turn on debug logging in the driver, etc.
Since problems usually show up when an app doesn't do what we expect, there is a tendency to identify the app as the source of the problem. Sometimes this is true, and often it is not true, as it is a device issue we see as an app failure. That's the case here, so I changed the title of the post accordingly,.