I was getting this on average once per hour after the 2.05 patch when I had literally never lost connection prior. The emergency fix explicitly mentioned the 90k disconnection error and that they intended to resolve it. Here's how they totally didn't:

2.05: Random disconnect. Error 90k. Try to log in. Breaks. Close client. Restart game. Back in. Occasionally alive.

2.05 Emergency Patch: Random disconnect. Error 90k. Try to log in. "Your character is still logged in..." message. Try again. And again. And again. And again. Back in. Dead as shit.

Good times!

Anyone else experiencing this?