NullReferenceException at OnPlayerExit
I tried to set up an ArenaDeathmatch today, and everything went smooth untill people started shooting. Most (if not all) players got disconnected when they fired a bullet. I also noticed that when i changed flags through the GUI everybody on the server started rubberbanding/lagging like crazy.
I found this on console:
NullReferenceException: Object reference not set to an instance of an object
NullReferenceException: Object reference not set to an instance of an object
  at Oxide.Plugins.ZoneManager+Zone.OnPlayerExit (BasePlayer player) [0x0001e] in <bc93839370a94439b3fe823f4d9f2363>:0 
  at Oxide.Plugins.ZoneManager+Zone.OnTriggerExit (UnityEngine.Collider col) [0x00013] in <bc93839370a94439b3fe823f4d9f2363>:0 
I am seeing this as well, but I only created the size of the arena and set a few flags. Even when I unload ZoneManager it is still popping up in console.

NullReferenceException: Object reference not set to an instance of an object
Oxide.Plugins.ZoneManager+Zone.OnPlayerExit (BasePlayer player) (at <752c4cf0afef483fa12dc75ce660a6b2>:0) Oxide.Plugins.ZoneManager+Zone.OnTriggerExit (UnityEngine.Collider col) (at <752c4cf0afef483fa12dc75ce660a6b2>:0)