Hi is this notification suppose to work when users click the Accept / Reject button?
Will, it supposed to set the user action to Accept/Reject?
since it doesn't have a url when clicking, do this supposed to work or it just blank button?
The issue is tracked under
QCCR1E154782: If the XSS filter is on, links and images generated by tag will be lost after you update the notification template.
It is fixed in 2019.05 patch 1 and 2019.08
With that said, if the notification template got modified before the fix, the upgrade or patch would have not automatically resolved the issue. You can add the link back, the easiest way is to copy it from another environment or tenant.