For Loop skipping first iteration in OIC

We are trying to create Attendance integration that reads from APEX database and uploads it by REST API into fusion time card as shown in the screenshot. Our issue is that the first iteration for an employee isn't processed, say employee number xx has start time and end time in the 14th, 15th and 16th, then another employee number yy with different data. It starts reading and uploading after the first employee with all its transactions, any idea on how to fix it?