After some deliberation, it has been decided that invisibility, greater invisibility, and similar effects will no longer provide a +20 bonus to Stealth checks to avoid being noticed. The reasons are simple, but I will explain it in detail so that there is no confusion as to why this was done, and I will explain what it means for those who plan to make use of spells like invisibility or items like the ring of invisibility.
The Issue: Invisibility makes the subject immune to all sight-based methods of being perceived. However, it also added a flat +20 modifier to Stealth checks or Perception DCs which resulted in both a game balance issue and a verisimilitude issue. From a game balance perspective, the spell made the Stealth irrelevant except against creatures with see invisibility or true seeing. From a verisimilitude perspective it made little to no sense that being harder to see would make you harder to notice in other ways. Effectively, a person with a 1 Dexterity and a -6 armor check penalty would be able to take 10 and clank past most people without being notice. Likewise, it seemed to be limited to creatures under the effects of invisibility or the invisible condition and not an effect of total concealment. This means that if you have 3 people standing in a room, one blind, one invisible, and one normal, the blind guy can hear the regular guy with a Perception check but cannot see him, while the invisible guy gets a +20 to avoid being noticed by the blind guy.
The Change: Invisibility works as written except effects that make you invisible do not provide a bonus to Stealth. You have total concealment and you cannot be noticed by sight. That means that you can walk right past someone and unless their Perception beats your Stealth check they cannot see you. Yes this means Stealth doesn't automatically solve issues of walking around in heavy armor or carrying heavy loads, but it shouldn't have helped that to begin with.