this is trivial to reproduce ever since early stable diffusion models, it's not really an oai exclusive issue.

for example if you ask any of these models (just about any image-gen) to produce Japanese ukiyo-e art they will almost always produce it with a hanko[0] that has been seen a lot in historical art pieces, usually having nothing to do with the era or style of the replica but seen so often in 'Japanese artwork' that it's just permanently tokenized into it as a defining characteristic.

[0]: https://theartofzen.org/the-hanko-in-japanese-art-and-ukiyo-...