No, it's nothing to do with the display on the forum, it's the animation itself. The Victory animation should begin with the character in the same position as in the Default animation, and end with him in that same position. (Just like the Fidget animation.) The reason is that, before the Victory animation is played in-game, the unit plays the Default animation while waiting for the defeated enemy to play its Death animation.
However, Firaxis somehow misunderstood their own game, and they made the Vanilla units so that the Victory animation starts with the character in the same pose as in the Attack animations, so the Victory moves the character from the Attack pose to the Default pose. So many unit-makers have copied that since (I think including UtahJazz in his tutorial), not realising that it doesn't look right in-game.
I wouldn't worry about it in this case. It's not obvious in-game - if it were, so many people (including the original makers of the game) wouldn't have made the error. And your unit looks absolutely fine. But it's useful to bear in mind for the future, because it's actually easier to make a Victory animation that starts from the Default pose than it is to make one that starts from the Attack pose. You don't have to move the feet at all if you don't want to.