I don't think it should, but I'm not 100% sure there. I didn't move all of my armies last turn so it could be that your scout was on one of those provinces. I'll have a look at the turn when I come home.
Yeah, I think it works out that about 50% of the time, an attacking scout (or any army) interrupts movement in the province it attacks, if it attacks out of a province owned by its own nation. Most likely, being discovered while scouting does not have this effect.