Server crash (farm pigs near the Moon Stone and Walrus Camp)

Server crash at the moment when I farm pigs near the Moon Stone and Walrus Camp.

11:34:26]: Registering master server in EU lobby
[11:34:46]: [string "scripts/components/follower.lua"]:8: attempt to index field 'follower' (a nil value)
LUA ERROR stack traceback:
scripts/components/follower.lua:8 in (field) ? (Lua) <7-9>
   self =
      inst = 149984 - icehound (valid:false)
      OnLeaderRemoved = function - scripts/components/follower.lua:22
      _ = table: 0x1d041790
      canaccepttarget = true
   leader = 150861 - little_walrus (valid:true)
scripts/class.lua:30 in () ? (Lua) <23-32>
   t = table: 0x1ac05590
   k = leader
   v = 150861 - little_walrus (valid:true)
   p = table: 0x248c0f40
   old = nil
scripts/components/follower.lua:129 in (method) SetLeader (Lua) <113-143>
   self =
      inst = 149984 - icehound (valid:false)
      OnLeaderRemoved = function - scripts/components/follower.lua:22
      _ = table: 0x1d041790
      canaccepttarget = true
   inst = 150861 - little_walrus (valid:true)
scripts/components/leader.lua:92 in (method) AddFollower (Lua) <88-111>
   self =
      _onfollowerremoved = function - scripts/components/leader.lua:23
      inst = 150861 - little_walrus (valid:true)
      followers = table: 0x266754b0
      numfollowers = 1
      _onfollowerdied = function - scripts/components/leader.lua:22
   follower = 149984 - icehound (valid:false)

server_log.txt