Video-chat layout oscillation

[EdNutting]

I joined a video chat with ongoing event with my browser maximised and the menu and chat sidebars open. I was the only person in the room, no video, no screenshare. The layout immediately freaked out and started oscillating (vibrating) very rapidly between two sizes. It looked like maybe a scrollbar was appearing causing it to get stuck in a recalculation loop but not clear (I was in a demo at the time so couldn't investigate).

Just collapsing the left menu bar caused it to settle down to one size. I wonder if maybe we hit a boundary condition.