Main meeting whiteboard is blank after returning participants from a breakout session

I have a whiteboard in use throughout a meeting. During a meeting, some participants might from time to time be placed into a breakout room (there's no need for them to use/access a whiteboard during these breakout sessions).

It seems that, if a breakout session occurs during a meeting, that the main whiteboard for that meeting is blanked out once participants return from their breakout sessions - so the whiteboard content from before the breakout sessions is lost.  Is there a way to prevent this happening? ie for a whiteboard to persist throughout the duration of a meeting regardless of breakout sessions?