I noticed when playing Kensei after getting a light parry (my examples were on Raiders) I did not complete a heavy attack before they recovered from the parry.
Kinda hoping it's a bug because it caused me to lose two duels and it seems like it shouldn't happen like that.

If it is on purpose please reconsider this. I feel it's an unfair disadvantage for them to have, when you include the fact that their dodge guard does not give them enough time for the heavy swing either and basically the only real useful skills they have only work on inexperienced players and there's no way to get the upper hand against an opponent with the parry issue.