star wars - Does a lightsaber have a cauterizing effect when cutting off appendages, or not?

The reason I ask this question is because in A New Hope.. there is a scene when Kenobi cuts off Ponda Baba's arm, and we can see that it is bloody on the ground. However, if we go back to the newer (older) movies, there is a scene where Mace Windu snags the head off of Jango Fett. It appears as though it is cauterized by the heat and burning of the lightsaber itself. Also in numerous video games, such as the Jedi Knight series, dismemberment from lightsabers yields no blood and appears to automatically cauterize the wound. Any thoughts?

Edit - Almost forgot about the scene when Luke gets his hand snagged off - There is no blood!

Answer

The lightsaber is supposed to instantly cauterize the wound... from posts on

http://www.killermovies.com/forums/archive/index.php/t-356672-where-is-the-blood-in-star-wars.html

A lot of people are claiming it is simply a mistake in the first movies.

But in the Star Wars Wikia it states...

http://starwars.wikia.com/wiki/Lightsaber

A lightsaber blade was a mass-less form that neither radiated heat nor expended energy until it came into contact with something solid. The power of the energy blade was so great that it could cut through almost anything, although the speed through which it cut depended on the density of the subject. One important note about lightsaber wounds is that they rarely bled profusely, even when a limb had been severed. This is because the energy blade cauterized the wound as it passed, and thus even a severe wound did not tend to bleed heavily.

This means you may still bleed but not a lot from the lightsaber wound.

Edit: Also want to state I looked up more about cauterization...

According to this website

http://www.stuffyoushouldknow.com/blog/stuff-knows-guide-proper-adulthood-cauterize-wound/

When cauterizing a wound with fire... It states..

Next, get a stick or something else to bite down on because you’re going to need it. If you have alcohol, pour it on the wound to clean it as best you can. Now comes the moment you’ve been dreading, but it’s a move that could save your life. Gently press the hot metal onto the wound, holding it long enough to seal it, but not so long that you’re burning into your healthy body tissue. Try applying it in short bursts so you don’t overdo it, checking the bleeding as you go. When you don’t see any blood flowing, it means you’ve done a bang up job.

From this we can gather that cauterizing a wound sometimes takes a couple of tries... Even though a lightsaber may cauterize stuff instantly, perhaps it doesn't "always" stop 100% of the bleeding.