"Click to disable request closure notification" doesn't work - still sends notification

"Click to disable request closure notification" doesn't work - still sends notification

Hi!  We have done some testing and found that without a doubt, the "click to disable request closure notification" button is not working in our instance of Zoho.  We have tried to change some settings, but have not been able to fix the issue.  Is there a specific setting that could prevent this function from working properly?  The button is present and appears to work, but if you turn off notification and close the request, it still sends a closure notification.  This is true when you click close request, or when changing the status to closed/resolved/etc

Any help would be incredibly appreciated.

Many thanks.