Looks to me as if the bonus damage from judgement of the crusader is added in a separate damage number. Your +spell damage from gear is added in the "main" part of the damage.
Damage total is mostly the same unless the target is stunned, or there is a crit.
The "bugged" part of the spell does not do double on stunned targets, and so far I haven't seen it crit.
But there is also a small boost from the "Judgement hits xx for 34 Holy damage". This part should not exist at all.
Actually this made me think about how the stun/incapacitate multiplier works/should work.
Does it apply before or after +spell damage?