it seems that the terrain info is getting corrupted. Every now and then I will notice random holes in my walls/roads. Yesterday there was a big spike in a hole I had dug which was sharp at the top, so not so likely to be playermade.
They fill in like any other hole
They mostly appear in terraforming
A hole is not always visible to everyone
A hole is normally visible to many others
Holes will appear and disappear without being fixed over something like a day
In the Shinra city perimeter we normally have 2 – 4 holes at any time
A hole can be up to 5 meters deep
They are not holes in the ‘world’, you can see the bottom
They are V shaped that seem to form a point at the bottom