Microsoft are currently rolling out a fix for this issue and are actively monitoring the results.
To receive the update, Microsoft Teams must be fully restarted. This can be done by right-clicking the Teams icon in the system tray (located in the pop-up menu next to the clock in the bottom-right corner of the screen) and selecting "Quit Teams", before reopening the application.
If you experience any difficulties restarting Teams or continue to encounter issues after doing so, please contact the Service Desk for assistance.