CALPADS will expect STAS data for all students in grades K-12, including Transitional Kindergarten (TK) student who have primary or short-term enrollments. However, students enrolled in a Non-Public School or students receiving Home/Hospital instruction are exempt. For exempt students, districts must submit "Y" in the Attendance Data Collection Exemption Indicator, see CALPADS STAS File - Other Options.
It may have to do with how absence codes relating to Distance Learning are coded. The original recommendation was to use Independent Study Complete/Incomplete for absences related to Distance learning, but this was quickly changed to NOT tag those absences with Independent Study Indicators. However, if the school did not alter their ABS codes to remove those IS indicators, days will be duplicated and totals wrong in the STAS file. Adjust the Absence Codes Configuration at each school to make sure there are NO Independent Study indicators on them, and re-run the Update Attendance History process. This will correct the totals for the STAS Extract.