Saad appears to be an S2 issue, whereas EFC is facing an issue where ASADA may be able to slide AOD into S0 after a 6 month investigation and planning process, despite advice provided to the AFL, ACC and EFC to the contrary.
May not be an S2. S2 only refers to peptides, etc. Only reason S2 is the one getting mentioned is because that is where AOD may fall.
Most accidental failures i've read about recently are due to DMAA being in a pre-workout powder for example, which falls under stimulants (s6).