Service level violation happens when the replies to tickets or resolution of tickets don’t happen within the time interval agreed upon by agents and customers. SLA violations are taken very seriously, and Supervisors or Managers usually set up escalation emails to receive notification when a violation occurs.
If the SLA compliance % of your helpdesk seems to be decreasing over time, it’s a sure sign of your support team being understaffed. But you cannot jump to the conclusion without examining the SLA % of each individual agent. A single agent might possibly be responsible for the dip. In that case, admins need to make sure that the number and content of the tickets assigned to that agent corresponds to their skill set.