There are many instances during the end duels where either the VFX was unfinished, or there are compositing errors. That’s not a complaint though, as I know that ILM had limited time and budget, plus the VFX shots are very difficult to do.

The stunt blade is partially visible in several shots, plus the Lightsaber blade is incomplete in several shots, giving the appearance that the blade is cutting through legs and arms!
In one shot, Obi-Wan’s blade is in front of Maul’s blade, instead of behind it, with the hilt of Maul’s blade as well as his hand not being visible.
I’ve been steadily making adjustments to the blades and VFX; it’s a slow process though, as I’m going through the scenes frame-by-frame.