Never saw the scout part but advent rebels have been really weak to play against. Last game I played I took over all 5 of their planets with no resistance besides every gravwell having a single colony ship. Ended up finding their capital ship and a few frigates a half hour later in the star gravwell...by then they were dead anyway...free xp though... 

Set them to  hard mode too... A bit out of practice but I figured they would givea bit more trouble to a rusty old vet...

*Edited for spelling

It may be the AI's attempt to deal with mines, or maybe a new implemenation to get them to use martyrdom and timed explosives...

In either case, I've had it occur once in a game I've played and I just sort of lumped it in with all the other odd things the AI does...