I played The Valley campaign in 1.2.8. When I locked the target with a bomb instead of a missile, the wingman sometimes can engage my target, but not always. Not so sure if it was related to the task I assigned in mission planner. When I said "cover me", he goes SEAD as normal. Other commands for engaging didn't work at all. It seems that in the instant mission the wingman works normally.
Now it's 1.2.9. My A-10A became virtually unplayable. The game crashes all the time when RWR receives a mud spike.