APDL will not allow the Duty On time to be set after the departure time of the first leg. This includes a delayed leg in the event that the leg is delayed as a result of insufficient rest the prior night. If you just attempt to change your duty on time, APDL will not allow it and will automatically readjust your duty on time to the scheduled OUT time of your first leg. This prevents APDL from accidentally starting your duty day after you have reported for the first leg, which would cause incorrect legality calculations. You must first change the scheduled departure time of the first leg of the day, then APDL will allow you to adjust the Duty On time as appropriate.