I glanced over the paper and it appears that the generative model used for cifar-5m wasn't even trained with a proper train/test split. It was simply trained u

I glanced over the paper and it appears that the generative model used for cifar-5m wasn't even trained with a proper train/test split. It was simply trained until the FID on the training set stopped decreasing. That's a pretty good way to overfit a model -- especially on a dataset as small as cifar-10 -- so it's hard to trust that cifar-5m is a decent proxy for the underlying cifar-10 data distribution.