Autorun events run as soon as the map loads. If your first commands in the autorun is to give the events sprites, I wouldn't bother - just put the sprites on the events.
Autorun events loop by default. Exit Event Processing just makes them start again from the top, which could be what's causing the twitching effect. To turn them off, you need to either Erase Event (if you're never going to come back to this map), or turn on a self switch and create a second page conditioned by the self switch, with no other changes to triggers or anything (if you're going to come back to this map).