It might be due to the macOS device that doesn't yet have client-qt. Perhaps it will go away when macOS has client-qt. Sorry can't easily test as not in frequent contact the other 2 people who have the iPad and macOS devices. If client-qt macOS is available before 5th February (likely the earliest time that will be in contact with the people again) may be (sorry not certain) able to check with them again; however, don't let this stop closing this issue.
The error was reproduced on Saturday 13 March 2022; however, a new version of Jami has been released. When we can check again with the new version of Jami for GNU/Linux we will do so. If the mute button does not mute the microphone, we will create a new issue.
@ovari the original issue described in this ticket is fixed (mute audio + mute video = audio cant be unmuted).
However, as I mentioned, I have never reproduced your scenario. If you still reproduce the issue, please open a new ticket