Anyone else tried this?

At the bonfire linking Undead Burg and the dragon bridge, I just went into human form and I climbed the ladder, and was heading for the Boar, but the exit was for some reason in fog. That was weird, well I hadnt heard any invasion sound, so I just went back down the ladder and wanted to go through the Burg. When I came down the ladder, that exit was blogged with fog too, yeah I was stuck.

I went into the menu and wanted to relog but the Quit game was grey so it had to be an invasion, but where was the invader? I wandered around for 2 minutes, and then suddenly the invasion warning pops up. Fair enough a little lag or bug didnt hurt so I prepared for battle. Seconds went and I didnt see any invader, all I heard was barrels crushing. I then texted him, asking where he was, and he wrote back "In the room under the bridge"... so the room above me where I couldnt come to. I went up the ladder and started random hitting through the fog, apparently I was able to hit him through the wall... He then left my world, and all went back to normal... :| :|

Anyone experienced something like this?

It's an invasion "preparation" - sometimes you get invaded and sometimes the fog disappears on its own.
It happens frequently in the most crowded areas.

I don't think it's a bug for passing through areas, in fact if you go human and stand at the beginning of the Kiln or in the forest, it happens a lot even if you're there for quite some time without moving.
It's probably the way invasions work, maybe sometimes the game just can't connect you right with the people invading or something like that.

It's happened to me a few times while invading.