The following situation occurred when reloading the plugin:

05/30 11:40:34 | FerryTerminalEvent, NpcSpawn and WaterTreatmentEvent were compiled successfully in 1598ms
05/30 11:40:34 | Calling kill - but already IsDestroyed!? genericradiusmarker[1060305756]
05/30 11:40:34 | [Ferry Terminal Event] [INFO] 11:40:33 [FerryTerminalEvent] [INFO] Event ended
05/30 11:40:34 | [Ferry Terminal Event] [INFO] 11:40:33 [FerryTerminalEvent] [INFO] The Event has ended
05/30 11:40:34 | Unloaded plugin Ferry Terminal Event v1.1.2 by Yac Vaguer
05/30 11:40:34 | Unloaded plugin NpcSpawn v2.6.9 by KpucTaJl
05/30 11:40:34 | [NpcSpawn] Loading custom navigation mesh files...
05/30 11:40:34 | [NpcSpawn] File AirEvent_Floor1 has been loaded successfully!
05/30 11:40:34 | [NpcSpawn] File AirEvent_Floor2 has been loaded successfully!
05/30 11:40:34 | [NpcSpawn] All custom navigation mesh files have loaded successfully!
05/30 11:40:34 | [NpcSpawn] List of biome positions: Arid = 1986, Temperate = 2761, Tundra = 1154, Arctic = 531
05/30 11:40:34 | [NpcSpawn] List of road positions: ExtraWide = 1431, Standard = 1462, ExtraNarrow = 0
05/30 11:40:34 | [NpcSpawn] 2360 railway positions found
05/30 11:40:34 | Loaded plugin NpcSpawn v2.6.9 by KpucTaJl
05/30 11:40:34 | Loaded plugin WaterTreatmentEvent v1.6.0 by Yac Vaguer
05/30 11:40:34 | Loaded plugin Ferry Terminal Event v1.1.2 by Yac Vaguer

if you prefer to not force the NpcSpawn to reload all the plguisn you can remove the line that says 

//requires NpcSpawn

It is located in the first lines 

Changed Status from Pending to Not a Bug

Changed Fixed In to 1.6.0