On an episode of “what on earth” they found that a rotting tree trunk beneath the surface can cause this type of hole. I think that story was about a beach on one of the great lakes so tree issue more likely.
Devil’s chimneys. I’ve heard the old time sand dune trekkers around here would carry a fairly stout stick, held horizontally, in case they stepped on one. I found one...top of a dune with some dead treetops exposed. Probably buried trees of 50-60 foot height. I was spry enough to jump out, back then. A tube in the sand. About 16” diameter, 10-12 feet deep. Kinda creepy.