Since Collisions are processed at the end of the time step, in this situation the spawn/deletion event isn't happening until the beginning of the next time step....so you end up with the 1 frame delay.
Eventually I may add the ability to do in-place collision processing in the Collision operator, which can have detrimental effects in many situations but would solve the issue here...in the meantime you can move the Rotation/Force/Display operators to their own event, and send particles from the Spawn operator into that event. That way when the particles sit in the Spawn event until the next time step, they won't be displayed. You can also drop the sim time step down to 1/2 frame or lower to further alleviate this.
Eventually I may add the ability to do in-place collision processing in the Collision operator, which can have detrimental effects in many situations but would solve the issue here...in the meantime you can move the Rotation/Force/Display operators to their own event, and send particles from the Spawn operator into that event. That way when the particles sit in the Spawn event until the next time step, they won't be displayed. You can also drop the sim time step down to 1/2 frame or lower to further alleviate this.