I had similar issue with EP40 smart outdoor plugs (https://community.tp-link.com/us/smart-home/threads/topic/712196). All dropped off of my Google home on Oct 23rd in the afternoon. Tried to add to...

Plugs removed from Google Home randomly last night. Tried to set-up routines in the KASA app (since google rountines were not effective now) and Kasa app says they are deleted. Help. Thanks, Ben