Missplaced blocks - paper build 337

Hi, I’ve been plaing around with the paper server and so far so good. I’ve noticed something strange though. I installed some plugins and build some structures. Then in the morning I restarted the server (hosted locally on my laptop) I can see, that some blocks are misplaced. It looks like parts of some structures where cut, rotated and moved to random places. I enclose some screenshots to visualise the problem. The plugins installed are: HungerGames, PermissionsEx, PexTabCompleter, SupervVanish, Vault, VaultChatFormatter, WorldEdit, WorldGuard.

Could you please point me in the right direction what’s going on?