Thers is a bug in the new update with the damage judgement on the SAM Evasion challenge. If you ar eflying an armed craft, and drop a bomb, perhaps to cut your weight, upon explosion, it will count as aircraft damage. A possible solution could be swapping to the dogfight style damage where it only counts if its critical. The SAMS will anilliate anyway, so theres no need for any damage to fail.