Something must have changed recently, because I only started getting this within the last week and I think the only thing that changed was I updated the Kasa Integration to 6.5.2. Something was causing the Last Activity to update before this version, not sure what.
I just have it set for most of my devices to watch the Last Activity to be less than 24 hours, if not it does a refresh, and if it still does not update I get an alert. Handy to know if a device (Zwave, Zigbee or Wifi) gets knocked offline or locks up for some reason.