i know its the combination of 2 plugins but maybe it can be included 

this plugin: Vehicle Airdrops its a private plugin 

Failed to call hook 'OnSupplyDropLanded' on plugin 'DiscordEvents v1.0.1' (InvalidOperationException: Collection was modified; enumeration operation may not execute.)
  at System.Collections.Generic.Dictionary`2+Enumerator[TKey,TValue].MoveNext () [0x00016] in :0
  at Oxide.Plugins.DiscordEvents.IsEntityInList (System.UInt32 networkId) [0x00048] in <41dd34355d95460a896db17bcf0a86c7>:0
  at Oxide.Plugins.DiscordEvents.OnSupplyDropLanded (SupplyDrop entity) [0x0000c] in <41dd34355d95460a896db17bcf0a86c7>:0
  at Oxide.Plugins.DiscordEvents.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00154] in <41dd34355d95460a896db17bcf0a86c7>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <80b90e8213db44b29ec2d4111764172c>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0