I find it curious that machine learning is a branch of computer science given how much of it is actually statistical learning theory.

The go-to graduate level machine learning text "The Elements of Statistical Learning" was written by 2 statistics professors (one, Prof. Hastie, a fellow South African! :)

Granted, neural networks are often taught as a bolt-on lecture in statistics course machine learning modules but topics like regularization and a rigorous study of overfitting were born in stats departments.