Try moving the angle adjustments into event #36, where the bullets are created. I think this will reference the correct turret. I cannot edit your capx because I am using the free version and you are over 100 events (I think you could easily reduce the # of events in your project, though...)
Spread Shoot--------------->Spread---->Spawn Bullet 1
Bullet 1-->Set angle to Spread.angle-20
--------------------------->Spread---->Spawn Bullet 2
Bullet 2-->Set angle to Spread.angle
--------------------------->Spread---->Spawn Bullet 3
Bullet 3-->Set angle to Spread.angle+20