This animation is played often in combat and the floating blood spray occurs every time. As there have been so few technical issues with this game, I and others would be very appreciative should you decide to hotfix/patch/update this animation flaw.
If anyone is capable and willing of providing screenshots or video of this bug, it would be also be much appreciated.
(Note: There are two different frontal finishing moves in which Corvo strikes down on the opponents chest/shoulder, one which is slightly longer than the other. The extended animation does not feature this bug, while the shorter version does.)