You might have to play against normal (DE)/HD AI then if it is a CD AI issue. Also, the reason why AI does not build walls and gates anymore after CD Ai is because they not necessarily know how to properly build walls and gates contrary to a human player. They do not build towers anymore either, because they use it primarily as a defensive building instead of offensive contrary to human players similar to gates and walls. You did not specify the difficulty level , but at least in my personal opinion if playing against CD AI it should be set to at least hard difficulty because CD AI is actually the easiest AI to play against and not HD or normal (DE).

I usually play against the CD ai on hard and have not had issues before. I like turtling and sieges so I prefer the way it plays, Hd ai tends to just spam spears and skirmishers and the regular ai never trains unique units - or surrenders at the first sign of trouble

Not really looking for competitive high level AI just something fun and truer to history, It may not be the optimal way to play but that's never been my interest

With some further tests the older civs are working fine it's just the three ancient civs that struggle.

Originally posted by Bad_soup:

With some further tests the older civs are working fine it's just the three ancient civs that struggle.

I think that "tech issue" is more accurate for this and not bug related. It is still bad however even if it is a tech issue instead of a bug. Tech issues need fixing similar to bugs.

Tech issue as in many people notice this and not just a few, but in some cases it could also be the latter as well when it comes to tech issues meaning that few people have this problem instead of many. I have not tested these new civs yet as CD AI, but you are probably not the only one noticing this problem. Another example of something that was an actual bug instead of a tech issue is the dark gray civ icons from the diplomacy menu when I was playing any campaign or historical battle and while this issue was not specifically mentioned in the patch notes from update it was finally fixed for me. I am not 100% certain if this is a tech issue instead of a bug, but CD AI with the newest civs should be playing normally similar to every other civ on skirmishes and if they are not they need fixing.

That's fair I have confidence any issues will be looked at in time. When the Armenians and Bulgarians were released the CD AI couldn't understand how to produce the mule carts, that issue got fixed not too long after.

All in all not a high priority issue, just something that will hopefully be improved in time