SLO starting early

Hi Experts,

   I've noticed one of our SLO-s firing too early. The corresponding caldutyhours table sets the working hours from 10:00 to 17:00. The IM ticket has been opened at 20:31:01 and the SLO started immediately. How come? No calholiday or any other exeption... the SLO type is the very same on the sloresponse ticket: everything adds up, but still, the IM slo started up way to early.

Any ideas?

BR, Dávid