Hello,
I noticed a bug in Sellus Gravius dialog.
When he asks for your papers, he removes them form player's inventory. If you close the dialog at this time, without asking information about package, Caius Cosades etc that will move the questline foward, he will ask for the papers again, and again.
Maybe when he removes the papers, the quest stage must move foward, so if the player starts a new dialog, the Sellus Gravius will recognize that he has removed the papers, and open the common dialog with the new quests.
This is serious bug because if the player does this mistake, he will be forced to start a new game.

Morrowind