@borislav12 , generally the five year exempt status lasts for five calendar years from the first entry with F-1 --once in a life time. So if you came back with a new F-1, you may have exhausted your exempt status. Please provide dates when you first entered with F-1 and your second entry / renewal of F-1 dates.
FICA regs have nothing to do with the F-1 exempt status and/or whether you have passed the SPT. It is based on whether you are a student/ trainee and are performing education related work with EAD as a trainee and not an employee.
Does that make sense ? Is there more I can do for you ?
