The point’s not that it isn’t scientifically accurate, but that it feels off to me, even before consciously thinking about why.

Note how even in the original shot, the explosion follows the ship’s movement against the stars.

Looking at other ship explosions in the trilogy, it looks like whenever a ship is partially destroyed it maintains momentum, but if it is totally destroyed the debris cloud quickly slows down relative to other objects as it would in atmosphere. However, the explosion often does travel quite a bit in the ship’s original direction, and it’s often quite a brief flash of light, at least in Empire and Jedi.

All this to say that a sustained TIE explosion that remains mostly in place relative to the shot feels off to me, based both on physics and the style of the OT.