I just tested it in training mode, I really wish I had a capture card to show you the results.



First of, I tried getting hit where the sword is on frame 18, since it'd make sense for a hitbox to be there. Couldn't get it to work, I'd either phase through it, or get hit on frame 19 instead. I also tried getting hit on the front, where the hitbox would be if it stayed in the same as it is on frame 17, just like in your new GIF. I managed to pause right on frame 17, with Mega Man falling down on Cloud, his feet almost touching the green trail (a pixel or two away from a phantom hit I'm pretty sure), but when I pressed L again to unpause, I didn't get hit, either. Finally, I tested to see if the late hitbox lingered until the windbox, like on your GIF, and nope, it definitely doesn't.



So in short, it looks like your first GIF was correct, and there is no hitbox on frame 18 , as weird as it sounds. Unless it's some very special property, or I messed up myself, you can't get hit by Finishing Touch on that frame.



I guess it explains some of those seemingly random Finishing Touch misses.