[NOT BUG] City culture expands outside 3 tile radius?

[Diadem82]

Not sure if this is a bug or just a strange feature.

But the culture of my cities is merrily expanding outside the workable 3-tile radius. Even for cities that have not filled their 3-tile radius yet.

I can provide a save if required. But if it's not a bug there's no need

 

[MadmanAtW]

It looks from the XML that 3 tiles out is the max you can buy, but that a city will happily expand up to 5 tiles out.

 

[Vandraad]

Well that does what cIV did with culture just continually expanding further and further.