“Attempted to start an invalid broadcast session" whenever I stop sharing my screen

Hello! I teach online (over Zoom and Meet), and share my screen a lot.

Whenever I finish sharing my screen, I hit “stop broadcast”. Then, about 4 seconds after I hit it, a specific error message comes up:

Screen broadcasting

Live Broadcast to Zoom has stopped due to: Attempted to start an invalid broadcast session"

And then I have to click either “OK” or “Go to application” to get rid of it.

This isn’t the end of the world, but it’s an irritation about thirty times a day. Rebooting my iPad (Pro) doesn’t do anything, and the problem happens in both Zoom and Meet.

Does anyone either (1) know what’s causing this problem, or (2) have any general hunches about what I might try to solve it?

Much thanks!

The black screen of death: