Problem with Exception while calling NextTick callback

Is the Consola this message appears when killing an Npcs .
Does the mod RustReward need an update ?
Or can you fix it yourself ?

Version 3.1.9
Thanks for help

Error message

| Exception while calling NextTick callback (ArgumentNullException: Value cannot be null.
Parameter name: key)
  at System.Collections.Generic.Dictionary`2[TKey,TValue].FindEntry (TKey key) [0x00008] in <8ce0bd04a7a04b4b9395538239d3fdd8>:0
  at System.Collections.Generic.Dictionary`2[TKey,TValue].ContainsKey (TKey key) [0x00000] in <8ce0bd04a7a04b4b9395538239d3fdd8>:0
  at Oxide.Plugins.RustRewards+<>c__DisplayClass74_1.<OnDispenserGather>b__0 () [0x00070] in <172954062e4e44f7a2edcdbf90d67c82>:0
  at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <beb2b64691c64e2b95b99491bd85442c>:0

Hi, the message comes up when the NPC is lying on the ground after the kill with the knife .

I have noticed that it may also be related to BradleyGuards the first wave that spawns there when the Bradley arrives there then comes the message on kill If the mod is known .

The free mod from Bazz3l by Umod

Here is the latest message :

[RustRewards] No friendly name for LootContainer - Please notify author.
(19:36:42) | Exception while calling NextTick callback (ArgumentNullException: Value cannot be null.
Parameter name: key)
  at System.Collections.Generic.Dictionary`2[TKey,TValue].FindEntry (TKey key) [0x00008] in <8ce0bd04a7a04b4b9395538239d3fdd8>:0
  at System.Collections.Generic.Dictionary`2[TKey,TValue].ContainsKey (TKey key) [0x00000] in <8ce0bd04a7a04b4b9395538239d3fdd8>:0
  at Oxide.Plugins.RustRewards+<>c__DisplayClass74_1.<OnDispenserGather>b__0 () [0x00070] in <eedd49b918204252867a7df6772185fb>:0
  at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <beb2b64691c64e2b95b99491bd85442c>:0

Thanks for watching