I believe one of the first publications explaining the phenomenon dates back to 2015. https://www.sciencedirect.com/science/article/pii/S095869461... It details the formation of the holes, their size, etc. I remember sending it at the time as a contribution here, thinking the topic was worth interest. Unfortunately, it fell through the cracks. I had also submitted it for approval to the Ig Nobel committee (it diverges somewhat, strictly speaking, from the philosophy of the prize). I received a reply saying it would be reviewed.