the idea of occasionally give unit pretty annoying which when you need it you can't produce yourself and when you don't need it you get unit. why not making it, you only can produce that unique unit in the conquered city of that original civilisation. Example, you conquered russian city and you can only produce krepost and cossack in that city so it did stack not with other unique building and unit instead of getting it ocassionally.

Woops. Fixed. Thanks.

Its bugged?