Unnamed city states turned from barbarians

[newtociv6]

Every single city-states turned from barbarians are unnamed, missing from the list and cannot declare war on them by me or AI.

Playing the Westeros map with some small changes, nothing major. Is this a common bug with barbarian clans mode? I got tons of them after setting
BARBARIAN_TECH_PERCENT to 1 by mistake (most became too powerful for AI to deal with).

 

[newtociv6]

Confirmed that problem starts when city states are liberated for the second time. It works fine in the first time but then..