[0.952][Bug] Game contains a duplicate Altar, led by a duplicate Verga

I encountered a very bizarre bug in my current game as Resoln.  The first two empires I met were Ythril (like a dozen tiles to the southeast of my capital) and Altar (to the distant northeast; I've yet to see any of their cities).  I was forced to go to war with Ythril very early, but I was able to beat him with my Binding minions and death magic even though he rushed early military tech.  I forced them to surrender and took Verga as my vassal once he was down to his last city.  Then I explored a little further to the west, and encountered a second Kingdom of Altar, whose leader is a second copy of Verga.  I've never made a custom sovereign based on Verga or any custom kingdoms at all, so the game did this completely on its own.  I have no idea what to make of it.

My newly vassalized Verga.  Note the two Altars in the upper-right.

The second instance of Altar and its noble leader.

EDIT:  Here's the save:  https://www.dropbox.com/s/h1ayl6f2rhjse44/Double%20Altar%20%2B%20Verga.EleSav