Greetings Devs,
I have saved the game up to where this bug occurs. I have shutdown and reopened the game (sometimes that helps). In this case, unknown Civ #16 hangs and It is stuck. This hang has blocked further progress and Ill just restart a new game.
Attached is the save from my drop box. I have also attached the previous save as well. I did not zip them this time.
https://www.dropbox.com/sh/vo59p7413g912no/AAAJ1nnHVwBEevBq-VeVYxaaa?dl=0
Larsenex