HCA: Hermit Crab Association

First time hermie mom BTW. Okay so my medium (golf ball size) hermie went down 2 days ago and started digging. He didn't really show much signs of molting expect for eating and drinking/hanging out by the fresh and salt water dishes more than usual. Here's my question. Is it normal for him to be digging constantly for 2 days straight. I can see him and have a camera on him that I check on all the time. (I have high anxiety so I think I check on the camera more than 10-30 times a day and whenever I wake up during the night (S) HALLLP
He seems to have stopped right there in the picture since yesterday and just keeps messing with the substrate. I've had my hermies for almost a month now. Play sand / coco fiber 5:1 substrate 6 inches deep. Heat at 80 consistently and humidity 80-85. I order handmade food from Etsy and rotate through the 5 types. I just ordered a leaf litter that should show up today. Please let me know what y'all think. I've been trying to find blogs about this issue online and can only find articles about molting not the process of digging to molting.. thanks y'all:))

Oh yeah, they will dig all over the place sometimes. Sometimes they dig just for fun. I notice mine go down and come up a couple of times before actually going down and staying down for weeks/ months to molt. And when they go down to molt, they will often move location, so you can sometimes hear them scraping and scratching underneath and not see them at all.