I have three of these and have had great luck with the first two.
Two weeks ago I ordered a third Zen15 to control a small water pump. The On and Off work great, but it was not reporting power. After removing / factory reset / re-include, it still was not reporting power.
I found another driver to use on the ST forum that only needed a find and replace, and gave that a try. Power reporting still didn't work, but the other driver reported back that my new switch was on firmware 1.4, which is a new firmware that became available 2 months ago. My Zooz zen 15's that are working good are firmware version 1.3 . Zooz sent me what they called a "Pre tested replacement" , which arrived today. Still no energy reporting using the Hubitat driver. Switched to the other driver and verified this replacement is also firmware 1.4 . Not sure what to do now. I think I am going to ask Zooz if they can make firmware 1.3 available to me. They seem to think it is a problem with initialization when joining to Hubitat.
Did any of you have similar issues?
Screenshot from Hubitat driver
Screenshot from ST driver