Spells: Invis/ITU stacking

[Ortnit]

Seems as if spells casted on you after being invis kept the icon visible on the client, but the server did not recognize your invisibility (even though players could not see you).

There are other classic mechanics that can explain why some may not have been seen such as proper 'awareness / proximity range', where if you ran by a creature fast enough at the proper time then there was a chance that they wouldn't agro. This could further feed into the illusion that the Double Invis was working, when in fact people just got lucky.

Come on, you have to be lucky to run by blue scowling mobs without them attacking you.
Yeah, you can run by one pack, maybe even two. But at the 3rd mob pack your luck most likely ran out when you try to run by them basically without invis (although you think you are, since you still have the icon?).
I very much doubt, that people on live would not have noticed that you only saw the icon clientside, but weren't really invis serverside.

I started playing on live during Kunark, casting invis and ITU to get both effects was quite common and it did always work for me after i learned about it. This is in fact the first time i ever hear about it not stacking.