this is not crashing my server (not currently as one person is building) but may potentially become a problem. Every piece someone lays down gives this message even when not building in a zone.
(20:14:10) | Failed to call hook 'OnEntitySpawned' on plugin 'ZoneManager v2.5.15' (NullReferenceException: )
at (wrapper managed-to-native) UnityEngine.Component.get_transform(UnityEngine.Component)
at Oxide.Plugins.ZoneManager+Zone.OnBuildingBlockEnter (BuildingBlock buildingBlock) [0x00063] in <1fc00134e00f47a4b31904a1fee6b5f5>:0
at Oxide.Plugins.ZoneManager.OnEntitySpawned (BaseNetworkable entity) [0x0008a] in <1fc00134e00f47a4b31904a1fee6b5f5>:0
at Oxide.Plugins.ZoneManager.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00433] in <1fc00134e00f47a4b31904a1fee6b5f5>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <4452f821def6406d834e4149849fe7ea>:0