When working with a ticket we change the due date, save it. Change the ticket status to Pending and click Update the due date and time reverts back to the current date and time.
Does it say "Since few seconds ago from DATE-TIME" after update the status to Pending?
Ah!, it actually reads like "Pending since few seconds ago from DATE TIME". And, if you change the status to "Open" or whatever it was previously, it will show you the correct Due Date that was set by you.
Since the SLA timer is OFF for Pending status, the Due By will be at a stand still in this status and hence the change in text.