I reported it here https://forums.galciv3.com/464679. When I ran the "soak" command the Burran were actually building colony ships. After the pirates destroyed one, they would build another. I ran "soak" many times, and they built multiple colony ships every time. This was in version 0.95.5. I am going to load the save into 0.97.5, then run "soak" and see what happens.
UPDATE
I loaded the game, ran "soak" and watched to see what happened. Eventually, a colony ship appeared next to the Burran's homeworld, just like it does when I get the Ideology that gives a free colony ship. I tried it two more times with the same result. This is different from what happened originally. Perhaps there was a change from 0.95.5 to 0.97.5 took away the ability to build ships. There were other strange behaviors by the AI in these games that weren't present originally. I'm going to assume they were caused by the changes made to the AI between the two versions.