If an enemy attack has a status effect, like Stun, there is a chance for the effect to be applied to each hit, and if it is applied, another chance that it will work or not. However, if an enemy gets multiple hits, the status effect is applied to all hits after the first successful application.
If, for example, an enemy got 6 hits, and the Stun effect was applied to the second hit, it would also apply to hits 3-6 regardless of the RNG results.