In this time, on this planet, we are not always in court and are now often running things remotely.
We (Users) have found that sometimes, Zoom doesn't blank the screen as it should when you are in LIVE.
There are several solutions to this and it all has to do with Zoom settings.
Go to Settings/Share Screen and Select Advanced.
Choose "Legacy" or "Adaptive Copy without window filtering"
The second solution is to put a 95% black color doc in as a "blank" screen and use that to Blank OnCue but changing the settings in Zoom works.