shared screen pauses when zoom tools are used

I am a secondary teacher trying to run remote classes.

When I am sharing a screen (eg: video, powerpoint, whatever) if I access ANY zoom tools (chat, allow participants in, etc...) my sharing gets paused - if it is a video, it pauses and I must tap again to restart, if it is a powerpoint, I must tap before i can continue moving through the powerpoint etc...

This did not happen to me previously - it just randomly started.

I have spent many hours trawling through "how to" posts and videos and zoom instructions and tutorials - I cannot find how to fix this issue.

If you have the answer, please, please, please share.