Unable to sell property

Nothing happening on the GUI, on the server I see this:

Failed to call hook 'PropertyManagerDeleteCommandUI' on plugin 'PropertyBuying v1.1.11' (InvalidOperationException: Collection was modified; enumeration operation may not execute.)
  at System.Collections.Generic.List`1+Enumerator[T].MoveNextRare () [0x00013] in <2161c9885dd04ff291b79db9349c4b9b>:0
  at System.Collections.Generic.List`1+Enumerator[T].MoveNext () [0x0004a] in <2161c9885dd04ff291b79db9349c4b9b>:0
  at Oxide.Plugins.PropertyBuying.CodeLockManager (Oxide.Plugins.PropertyBuying+PropertyHouse property, System.String options, System.UInt64 playerID, RelationshipManager+PlayerTeam teams) [0x002bc] in <28116743834c445b9b3c0850e8c8a8ff>:0
  at Oxide.Plugins.PropertyBuying.PropertyManagerDeleteCommandUI (ConsoleSystem+Arg arg) [0x00073] in <28116743834c445b9b3c0850e8c8a8ff>:0
  at Oxide.Plugins.PropertyBuying.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x01072] in <28116743834c445b9b3c0850e8c8a8ff>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <87ce9ac9776a48658bc55eae6debe38b>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <18d4f19bbc844191b11ed9e69284d09b>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <18d4f19bbc844191b11ed9e69284d09b>:0
Calling 'PropertyManagerDeleteCommandUI' on 'PropertyBuying v1.1.11' took 503ms
Failed to call hook 'PropertyManagerDeleteCommandUI' on plugin 'PropertyBuying v1.1.11' (InvalidOperationException: Collection was modified; enumeration operation may not execute.)
  at System.Collections.Generic.List`1+Enumerator[T].MoveNextRare () [0x00013] in <2161c9885dd04ff291b79db9349c4b9b>:0
  at System.Collections.Generic.List`1+Enumerator[T].MoveNext () [0x0004a] in <2161c9885dd04ff291b79db9349c4b9b>:0
  at Oxide.Plugins.PropertyBuying.CodeLockManager (Oxide.Plugins.PropertyBuying+PropertyHouse property, System.String options, System.UInt64 playerID, RelationshipManager+PlayerTeam teams) [0x002bc] in <28116743834c445b9b3c0850e8c8a8ff>:0
  at Oxide.Plugins.PropertyBuying.PropertyManagerDeleteCommandUI (ConsoleSystem+Arg arg) [0x00073] in <28116743834c445b9b3c0850e8c8a8ff>:0
  at Oxide.Plugins.PropertyBuying.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x01072] in <28116743834c445b9b3c0850e8c8a8ff>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <87ce9ac9776a48658bc55eae6debe38b>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <18d4f19bbc844191b11ed9e69284d09b>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <18d4f19bbc844191b11ed9e69284d09b>:0
Calling 'PropertyManagerDeleteCommandUI' on 'PropertyBuying v1.1.11' took 502ms
Calling 'OnPlayerInput' on 'PropertyBuying v1.1.11' took average 1009ms
 

This problem never came back, there's still a delay selling properties but I'm at least able to sell them.