[otrs] escalation email notification question

hi, we have the really strange behavior that when a ticket was escalated at some time and the notification has been sent to the agents in question, this ticket will generate every day between 8.00am and 8.05am again a notification that is again sent to the agents. first of all i thought that this has to be in association with the defined working hours in the otrs framework. but it is not... it doesn't change something if the working hours starts at 1am or 11am or even 4pm... the escalation notification will alway be sent again every day between 8.00am and 8.05am... why? does anyone of you guys have an idea on this issue? thanks a lot. regards, patrick.