Here's the sequence of events:

1. I win Godfather prior to being given any sort of custom title.

2. I get a custom title. This removes "Godfather" from my title, which causes the "leaders" command to no longer show me as Godfather, even though I still have all the guild leader skills and retain the power to blackball.

3. Someone else calls a Godfather vote.

4. I win the vote, and get these echos:

You are now the Godfather of Voralian City.
You have gained the skill city ties.
You have gained the skill shopkeeper favors.
You have gained the skill guild protection.

5. This resets my title to "{custom part}, Godfather of Voralian City" and removes "Marshall of the Fortress" from the end. Also, my skill percentages in the three guild leader skills all get reset to 70%.

This is because thief guild stuff is handled by title, which is really prone to breaking.

It's on my project list to revamp how that is tracked and how it works. This will be fixed when I do that, but as it's part of a bigger project, it sits for now.