I notice sometimes that the NPCs placed using maspawngroup and maspawnpoint sometimes immediatly respawns and IDK why. I chauked it up as a plugin bug. For example I have an NPC placed on oilrig

"oilrig_1": {
      "SpawnGroups": [
        {
          "Id": "d5bbe735-b48e-46fa-b727-cf1b2a85aa6f",
          "Name": "OILRIG1_NPC",
          "MaxPopulation": 1,
          "SpawnPerTickMin": 1,
          "SpawnPerTickMax": 1,
          "RespawnDelayMin": 3000.0,
          "RespawnDelayMax": 3600.0,
          "InitialSpawn": true,
          "Prefabs": [
            {
              "PrefabName": "assets/rust.ai/agents/npcplayer/humannpc/scientist/scientistnpc_heavy.prefab",
              "Weight": 100
            }
          ],
          "SpawnPoints": [
            {
              "Id": "0c614c3c-149a-48f6-829d-61f5b428de2e",
              "Position": {
                "x": 10.3437214,
                "y": 45.1299973,
                "z": 5.75925636
              },
              "RotationAngles": {
                "x": 0.0,
                "y": 267.603424,
                "z": 0.0
              },
              "Exclusive": true,
              "SnapToGround": true
            }
          ]
        }
      ]
    }​

and for whatever reason it respawns it immediatly sometimes. Take note that I tried this on a test server with the latest updates with carbonmod and monument finder&addons as the only plugins. This happens to any NPC placed but I havent noticed it happen to crates. "Not saying that it cant happen".

One possibility is that the NPC was killed at a time that aligned with the schedule. Spawn groups in the plugin work the same as vanilla Rust in that the schedule doesn't pause after the entity has been spawned. This means that the time to respawn is only at most the time you configured. You can try addressing this with the PauseScheduleWhileFull option.