Shadowhunter leaping blow appears to be bugged in rowen as the hard cc is applied at random, sometimes it only knocks down enemies without applying the earthquake status effect, while other times it stuns enemies correctly.
So I had some more time today recorded a bunch of gameplay in rowen and picked out the interesting parts:
In the first 3 clips you can see how the skill is intended to work, this is how it works in pve (for example prokel), arena pvp (normal and ranked) and open world duels.
The 4th clip shows an example of the “immunity rate” indicating that the game is trying to apply the earthquake effect, but is overruled by a knockdown effect that should not exist on that skill (I specifically picked this one as it shows a player out of combat, which means that he/she could not have hard cc immunity active from previous encounters).
The 5th clip shows an even rarer bug where neither effect is applied, and where the enemy is staggered instead. Notice the lack of “immunity rate” which always indicates an enemy that is unable to get hard ccd for different reasons.