Part of Space Station Deleted

[USABxBOOYO]

I was building a massive hangar today for my Titan that I had recently built in my faction home. I started by extending a PlexLifter shaft down about a hundred blocks or so and then started building. I built for about half an hour. Eventually my FPS started dropping when I placed any blocks, so I exited the game to apply linear mag filters in the hope that it would help. When I came back a few seconds later, the entire area I had built (around 80000 black hulls) had been completely deleted and my blocks were not refunded. Everything else on my space station was normal and intact and my ships were just where I had left them, but all that remained of my new area was a stub of the PlexLifter shaft. This was on a vanilla server with default settings.

Has anyone else had this problem before?