End users may get confused that some tickets under "Closed Tickets" have "completed on" display nothing instead of the closed date of tickets. This tech doc explains why and what SDM admin can do to display a "completed on" date for all closed tickets.
Release : 17.3, 17.2
Component : SERVICE DESK MANAGER
This works by designed.
This is due to the fact that Cancelled status does not make ticket resolved and SP looks for resolved date not closed date. Therefore, if you want the date value displayed for all closed tickets, you would need to have Cancelled status' "Ticket Resolved" field checked.