If before/after school or any other periods throughout the day are imported from Timetables into PxP as 'Other' and rolls are unable to marked for classes in these periods, you will need to modify the Period Type by going to:
Class PxP > Class PxP Setup> Timetable/Period Setup > click on the period > Set Type: Period > ensure that Sync to Attendance options is DISABLED** > Save.
Note: You cannot synchronise PxP classes to Attendance that fall outside of School Start/End times - if you require specific school years to have varied start/end times, please ensure this is configured within Attendance > Attendance Setup > School Times.