In privacy dashboard > microphone usage, it shows jitsi at times where general microphone access was granted, but jitsi was fully closed and not running in the background.
Discussion
Yeah that's odd. I know I occasionally get the location icon unexpectedly appear but when I check, I've left an app running. It disappears when I close it.
My gut feel is that you've got a rogue app that's accessing your microphone.
It'd be cool if Graphene told you what was accessing the mic.