Yikes! I feel silly that it took me so long to figure out what you meant. I just wasn't expecting it because it wasn't meant to be there.

This will be fixed in the next release, which incidentally will be dropping later this week.

But if you'd prefer to fix it manually (rather than upgrading) it is really simple.

Open /include/class.queue.php

Change line 1775 from:

return '<div class="overdueTicket-container"><span class="Icon overdueTicket" data-dropdown="#action-dropdown-statuses" data-placement="top" data-toggle="tooltip" title="Ticket is Overdue!"></span></div>';

To:

return '<div class="overdueTicket-container"><span class="Icon overdueTicket" data-placement="top" data-toggle="tooltip" title="Ticket is Overdue!"></span></div>';

Thank you so much for taking the time to bring this to my attention, @mcmastertech!