Hello. I've noticed this too, though it seems to only be cosmetic, it still functions as 50% from what I can tell. But there are some other bugs. For one, enemies slain by sirens will only show their "damage taken" animation instead of their "death" animation. The damage will sometimes appear over their heads late, and/or be registered the following round (the latter seems to happen mostly for bosses, however). Also, in my experience, it only removed one blade as supposed to the two written on the card. Not sure which is in error though, lol. This is all I have noticed for now, I'll edit if there is anything else. I'll also be posting this in Halston's Lab tomorrow.
Cya in the Spiral
Paul Stormglade, Transcended Diviner
EDIT: The cause of the animation mix up is simple, the damage taken animation runs, but they don't have time to run their defeat animation. I discovered this when a Greyhorn Mercenary began his death animation as he faded away.