There appears to be an issue in the layout of Nextcloud Talk’s full screen view, which affects Safari and Google Chrome on OS X only.
When Nextcloud Talk’s full screen mode is selected during a call, the video of the chat partner(s) and the inset video of the affected user do not appear in the new view. All icons and audio are still available. If turned on, the chat column renders in a strange way: towards the centre of the viewport.
Once full screen mode is turned off, the missing functionality is immediately restored. This leads me to believe that this is a front end issue which only affects certain browsers.
Nextcloud Talk 8.0.8
Thanks for your guidance!!