This is a warning that your microphone may not be muted when you push mute in conference calls.
Two data scientists looked into whether or not the microphone on your device is actually turned off when one pushes mute. In most cases, it turns out that the mute button disables fellow attendees from hearing you but it does not disable the application you are using from hearing you. Software programs actually keep access to your microphone even if you push mute.
According to TechXplore, “They found that all of the apps they tested occasionally gather raw audio data while mute is activated, with one popular app gathering information and delivering data to its server at the same rate regardless of whether the microphone is muted or not.”
This was true in most video conferencing apps on iOS, Android, Windows and Mac. You can turn off your microphone in your device settings but most people don’t do that. They trust the mute button to actually mute. But now you know you shouldn’t so behave yourself when you’re on a call!