MacOS: Cannot stop No Permission to use Siri Popup every 20 seconds

One of my staff members is having a problem with their MacBook Pro every 20 seconds whilst they're in the office. Normally triggered by "Hey Siri," however just general conversation in the office is triggering the popup below. It can popup every 20 seconds with words that sound slightly like 'Siri' which has been frustrating to watch, let alone the staff member. How do we stop this popup? []