Has anyone seen this before?

So during Thanksgiving break, on Saturday I noticed the bathmat next to the shower was a bit wet, I thought I must have not dried off enough. Next morning, I went to use the restroom in the master bath, and the other bathmat was wet. I looked down and noticed water going through the laminate flooring.

Went back into the bedroom, went to the wall adjacent to where the shower is, and the carpet was soaked at least 5 feet from the wall towards the bed. Immediate oh shit mode, ran and turned off water to entire house. Tore up carpet on that side, grabbed fans, dad came over to help me diagnose what would later turn out to be a pinhole leak in the water supply to the shower. In the process of opening up the walls, we found a absolute shit ton of dirt, packed in behind the shower, all the way up and around it, and up to underneath where the seat is. It's a installed shower, not titled, so there's space, but the amount of dirt is incredible. Has anyone seen this? I've had a couple people say gophers, but the amount of dirt makes me think away from that and more towards when the people who installed the shower years ago, they used dirt as a fill behind the shower.