Additional chat-related features and issues within Microsoft Teams for business
I was able to come up with a workaround, but it requires you to use a web browser to have the Teams meeting. (Fine for me as I'm on Linux and there isn't a native Linux version.)
First, I installed the TamperMonkey browser add-on. Then I created this script:
/*
==UserCSS==@name Hide Teams "your microphone is muted" popup@match https://teams.cloud.microsoft/*@version 1.0==/UserCSS==*/
div:has(> div > div > #ufd_content_DeviceSpeakWhileMuted) {display: none; }
This script works by simply hiding the popup. (So technically it still pops up, it's just invisible.) Once I enabled this script, I no longer saw this annoying popup appear every few seconds.
If TamperMonkey isn't available for your platform, there are alternatives that you might be able to use instead (FireMonkey, GreaseMonkey, etc.)