Grant Access dialog box no longer popping up when commenting in a sharepoint list

We have a sharepoint list to manage support tickets. We need to contact an user to ask extra questions we use the comment functionality. 

Before we received a popup to grant the user access to the ticket.

Sinds the first of September the popup no longer comes up.

When we add a comment now the website just hangs. If we add the rights to the record in the sharepoint list and add the comment then that works but we would like to get the grant access dialog box again.