random hand raising on chrome webpage zoom in chromebook

Writing for my elderly parents, using zoom for religious meetings, on chrome web browser, on their chromebook.  They report that their hand raises without their raising their hand.  It is proving to be disruptive to the meeting, because they are continually being called on, but have nothing to say.  He keeps trying to lower his hand, but then sees it up again.  Is there any setting adjustment I can help them with to stop this from happening?  Thank you so much, in advance.