The most weird thing started happening.
One of my HD+ dashboards is executing actions "by itself"!
It started on Monday when I was not home (nobody was), I got back and some lights were on, and the dashboard was showing a folder, which was not how I had left it.
Initially I thought someone had come in somehow, checked the door lock logs, nothing. I was very puzzled, then around half an hour later I saw it with my own eyes. I was looking at the tablet, with HD+ opened when it executed around 6 different actions very quickly, faster than a human being could have. Some actions were on tiles set to prompt and PIN, so some pop-up windows were left open.
It happened again twice in the following 40 minutes.
I switched off my Internet router for a couple of hours, researched about incoming connections on UniFi Gateway, and learned that they are blocked by default, a configuration that I didn't change.
I switched the Internet router on again, which got a different public IP address, and everything was fine until today, when again some actions were executed, this time it was more scary, the front door was unlocked! I was alone at home.
This Fire HD where the weirdness is going on is dedicated to HD+ dashboard, it is running for 2.5 years without previous issues, the only other app installed on it is "Keep Screen On Free".
I have a total of 5 Fire HD and 2 Android phones dedicated to dashboards, "Cloud Mode" is off on all of them, and only 1 has been affected by the problem (so far).
Any ideas?