BigBlueButton is a plugin in our MoodleCloud sites run by Blindside Networks. During 2020 they were seeing increased pressure on their servers to handle so many webcams. They’ve also seen students on low bandwidth getting disconnected when many other students in the session shared their webcams.
To reduce the overall load and to reduce the disconnects (which makes it hard for students to participate), they have temporarily enabled the webcam Lock Settings so students do not see other student's webcams.
You can find more information regarding this setting in this Moodle forum discussion.
*If you are having issues with your BigBlueButton we suggest you get in contact with Blindside Networks, who own the plugin.