1.9.x is end of life and no longer supported. Please upgrade to current and re-test.
SLA listed there is the name of the SLA that is applied to the ticket (in your case 10 dias).
You would need to edit that SLA and see what the timer is set in the SLA.
Admin panel -> Manage -> SLA
Click on 10 Dias
See Grace period (in hours).
The due date will will also be impacted by any schedule that you have set here also.