Any cloud spells (unless it was already corrected) like silence, grease, web, caltrops and what not, dispel invisibility whenever someone is affected by it.

In other words, say you cast web, then invisibility, then someone goes in the web, your invisibility is dispelled.

I don't think it's possible to fix this one. As I understand it, invisibility is automatically (at the game engine level) broken when you attack somebody, and having a victim wander into your AOE spell is treated as an attack.

This is correct. This also affects things like Caltrops, wall spells (blades or fire), or any other harmful effect that is longer than instantaneous.

Well, if that doesn't royally suck, then I truly don't know the meaning of the word "suck".