Bumping this, but also providing a bit more troubleshooting information!!

After getting 90002 twice during a single The Steps of Faith trial, I decided to try a solo instance to see how that would work. I made it through Satasha solo without a single 90002 so I thought I might have been onto something, but then I ran Haukke Manor solo and during combat with the skeletons in the basement *SNAP* 90002 again. After that I finished the instance without another error, and ran Ifrit solo. No 90002 on Ifrit. After that I decided to try solo Haukke Manor again but this time just sat still to see if a disconnect would happen. I waited for about forty minutes without a 90002 . . . and then was kicked from the instance due to inactivity. No 90002 though - I was just returned to Ul'dah.

Based on my tests it is still 100% an issue that happens inside of instances. It doesn't seem to be strictly caused by instances with other players, but I do believe that having other players makes it more likely. While more testing is needed, it looks like 90002 won't happen unless I am active. Combat, in particular, seems to be the most reliable trigger. It must be stressed though that this is only true inside of instances - I can run however many leves, FATES or whatever outside of an instance I want without an issue.

I hope this information is useful! Thanks!!