I simply doubt the wingman was in a position to 'carefully aim' when releasing his bombs: his jet…

So, yes, wingman's second bomb hit something and caused secondaries: by accident.

I simply doubt the wingman was in a position to 'carefully aim' when releasing his bombs: his jet obviously lurched upwards due to the shockwave from detonation of leader's bomb.

So, yes, wingman's second bomb hit something and caused secondaries: by accident.