homepod mini randomly playing music or activating itself

I have a problem with one of the HomePod minis. Two HomePod minis are working fine, but the third one has started randomly playing music on its own or even executing commands and saying: "Sorry, I can't do that, but I can search the web for you!"? It all started a few days ago - so far everything was OK, no automation is enabled or anything similar, I haven't changed or added anything during this time.

I noticed that the Apple HomePod mini randomly activates itself and listens to the surroundings. After about a minute, it starts playing music or responding to random conversations we have. In between, when the colored LEDs are spinning on the HomePod screen, it is unresponsive to commands: if you say "SIRI STOP" or any command at that time, it doesn't respond - it just listens to something on its own!

This happens regularly randomly - I can't leave it plugged in because it triggers itself.

So far, I have checked all the known things that could affect this:

• I don't have any automations connected to HomePod.
• I have reset the HomePod several times.
• I have removed the HomePod from the Home app and iCloud and reconnected it to Apple Home.
• I only have access to Home on my home WiFi.
• The Apple HomePod screen is clean.
• I have reset the Apple iPhone several times.
• WiFi has been reset several times.

I simply don't know what could be wrong for the speaker to randomly activate itself, not only playing music but often responding as if someone asked it something or gave it some command!? But it always starts spinning the colored LED screen on the speaker before that on its own.

I have a smart home with many integrated smart switches and sensors, most of them from Aqara, and everything is connected to Apple Home. Only this speaker has now started malfunctioning, and I can't have it plugged in at all.

Thanks for your help.