My friends and I are playing Astroneer together on pc and I am hosting the server. One of my friends decides to join me as I am digging in an underground cavern. Suddenly while digging, my friend tells me that I just went through the wall. On my screen I could not see anything wrong going on, I was just in a tunnel within the cave going deeper, but to him there was no tunnel and I was just walking through the ground as if it wasn't there. He attempted to follow me thinking it was a simple graphical error but alas, he could not go through it and on my screen looked to be walking in mid air. My friend decided to dig through it and it worked, however a few seconds later the ground he dug had reappeared. One time he dug a hole in the weird ground and went inside as it was dug out and it reappeared over him and spit him back to the top, killing him with fall damage. My friend later came back down the cave and tried to simply stand on the weird ground and died instantly for no discernible reason. Later we switched hosts and switched to a different save and I came upon the weird ground bug, I never died because I didn't stand on it, but when I tried to dig through it it would just reappear and I couldn't progress any further in the caves. as for reproducing I'm not sure how, every time we logged on the problem would appear but I haven't seen this glitch anywhere else. I simply loaded up my single player save, and the others joined me via the interface within Astroneer. The same technique for joining was used on the new save with the new host.