Is a ship with a Stealth Device hit by an Ion Cannon about to loose its Stealth Device?

I would have thought so, but the wording concerning Prince Xizor in the new FAQ seems to suggest that a ship hit by a number of Ion and Stress-generating weapons is actually not considered hit by an attack.

Now, Prince Xizor might just be an exception and we shouldn't think more of it, but on the other hand the rules tend to favour generalised takes on similar aspects of the game.

You're reading too much into that.

Nothing about that changes if the ship is Hit or not, it's just saying that he can't move uncanceled <hit> and <crit> results to another ship.

So yes a ship hit by an Ion cannon will still lose it's Stealth Device. This of course assumes that ship is actually Hit.

The FAQ is trying to clear up what Xizor does and when. While the vast majority recognized that if you shot Xizor with an Ion Cannon and hit then Xizor will suffer the consequences. There was a small number who wanted to say that you could move a die result away from Xizor to another ship BEFORE the compare results step allowing Xizor to be missed by an attack.

A ship that is hit by an attack will lose its Stealth Device even if the final result of that attack deals it no damage.