So PS4, day 95, and I've been back and forth over a stretch of random-gen between two biomes. On the way back from a ore run, there's an open cave that wasn't there a few hours before.
Could be it was a cave just under the surface and going over it was enough to overload the structure to collapse it. There was a bug a while ago that caused these holes to appear in roads - how old is your save file?
