If you are using also supervisions in your timetable, then duties of missing teacher will be also displayed among his lessons, wnich need to be substituted.
You can then set substitution of this supervision duty in same way as for standard lesson, or you can also cancel this supervision.
- do not forget to have correctly synchronized your timetable with edupage (each classroom has to be linked, otherwise supervisions will be not displayed).
Teacher's absence on supervisions
How can I cancel the lesson