If you started working on the first day of school (for example, on 9/4), your first check (for example, distributed on 9/14), will be less than the regular, full amount. This is because there are days in the pay cycle (in this example, 9/1 through 9/3) which you did not work. These non-working days may be shown on your paycheck as a negative adjustment.
This only affects new hires on payroll banks Q742 (pedagogues) and Q744 (paraprofessionals), who are paid semi-monthly.
Your second paycheck will reflect a full pay period.