A couple patches ago, a few "invisible walls" popped up in West Athen and SWB Last Ditch. They are invisible, right in the main pathway, and only about a foot or two high, so you can jump over them. The one in West Athen is near the Reclaim/Save/Bank area, a bit toward the advanced store. There are a couple in SWB Last Ditch - one in the hallway by the Wompa, heading toward the Reclaim/Save/Bank area, the other couple are in front and behind the Reclaim/Save/Bank area. -Another characteristic to note about these "invisible walls" is the fact that they are one-way, meaning they only block you if you are trying to go a certain direction, not when you are coming from the other direction.
I am sure there are others that people have noticed elsewhere, but these are the only ones that I have found, and it would be nice if we could have them removed.