Crash upon being attacked by a thunderbird

Stack traceback from ~/.klei/DoNotStarve/log.txt:

scripts/components/seasonmanager_pork.lua(1775,1) thunderhat	
scripts/components/seasonmanager_pork.lua(1775,1) ancient_robot_leg	
scripts/components/seasonmanager_pork.lua:1776: attempt to compare nil with number
LUA ERROR stack traceback:
scripts/components/seasonmanager_pork.lua:1776 in (method) DoLightningStrike (Lua) <1768-1818>
   self =
      summerlength = 0
      winterenabled = false
      dryenabled = false
      hurricane = false
      hurricanetease_start = 0.5
      lightningdelays = table: 0xdf14420
      segmod = table: 0xdf13a00
      summerenabled = false
      current_season = temperate
      fog_transition_time_max = 10
      lushlength = 10
      hurricane_gust_period = 0
      seasonfns = table: 0xdf139d0
      greensegs = table: 0xdf0fb00
      current_temperature = 39.942487592856
      nextlightningtime = 5
      aporkalypse_enabled = true
      lushsegs = table: 0xdf0cd10
      precipoutside = false
      preciptype = rain
      base_atmo_moisture_rate = 1
      fog_fadetime = 5
      ground_snow_level = 0
      humidlength = 10
      moisture_limit = 1032.1596982666
      inst = 100024 - porkland (valid:true)
      aporkalypse_length = 10
      hurricane_duration = 0
      springsegs = table: 0xdf0ad10
      aporkalypse_segs = table: 0xdf12810
      summersegs = table: 0xdf0aef0
      fog_state = 4
      autumnenabled = false
      moisture_floor = 0
      summerfreq = table: 0xdf0ad70
      wetlength = 15
      wetenabled = false
      rain = 119234 - rain (valid:true)
      temperatesegs = table: 0xdf115c0
      noise_time = 756.13337276876
      hail = 119235 - hail (valid:true)
      bloom_time_current = 0
      bloom_enabled = true
      precip_rate = 0
      windy = false
      bloom_modifier = 0
      mildlength = 20
      bloom_time_to_new_modifier = 0
      snow = 119233 - snow (valid:true)
      hail_rate = 0
      summerdsp = table: 0xdf0af20
      atmo_moisture = 382.79654976559
      wildfire_retry_time = 45
      springenabled = false
      winterdsp = table: 0xdf0ad40
      winterlength = 15
      humiddsp = table: 0xdf13a30
      fog_time = 0
      hurricane_wind = 0
      windmode = dynamic
      peak_precip_intensity = 1
      wither_delay = 35
      mildsegs = table: 0xdf0e420
      precipmode = dynamic
      hurricane_gust_timer = 0
      incaves = false
      percent_season = 0.1
      greenenabled = false
      lushenabled = true
      temperateenabled = true
      hurricaneoutside = false
      drysegs = table: 0xdf0fd20
      lightningmode = rain
      humidenabled = true
      mildenabled = false
      ininterior = false
      hurricane_timer = 0
      wintersegs = table: 0xdf05fa0
      wetsegs = table: 0xdf0e620
      temperatelength = 10
      drylength = 15
      hurricane_gust_state = 0
      greenlength = 20
      autumnlength = 20
      springlength = 0
      hurricane_rate = 0
      seasonmode = plateau
      rejuvenate_delay = 43
      hurricane_gust_speed = 0
      hurricane_gust_peak = 0
      humidsegs = table: 0xdf11b40
      initialevent = true
      precip = false
      hurricane_peak_intensity = 1
      autumnsegs = table: 0xdf05f70
      hurricanetease_started = false
   pos = (-545.38, 0.00, 443.55)
   ignoreRods = nil
   rod = 121185 - thunderhat(LIMBO) (valid:true)
   player = nil
   rods = table: 0x1aab0f40
   k = 2
   v = 116453 - ancient_robot_leg (valid:true)
scripts/prefabs/thunderbird.lua:35 in (field) fn (Lua) <31-36>
   rad = 7
   angle = 4.1887866666667
   pos = (-545.38, 0.00, 443.55)
scripts/scheduler.lua:195 in (method) OnTick (Lua) <169-226>
   self =
      running = table: 0xd309fa0
      waitingfortick = table: 0xd309fd0
      tasks = table: 0xd309f50
      waking = table: 0x1fe381a0
      attime = table: 0xd30a060
      hibernating = table: 0xd30a030
   tick = 23050
   k = PERIODIC 119543: 0.400000
   v = true
   already_dead = false
scripts/scheduler.lua:402 in (global) RunScheduler (Lua) <400-408>
   tick = 23050
scripts/update.lua:105 in () ? (Lua) <90-191>
   dt = 0.033333335071802
   tick = 23050
   i = 23050

scripts/mainfunctions.lua(864,1) LUA ERROR stack traceback:
        scripts/mainfunctions.lua(864,1)	
scripts/mainfunctions.lua(865,1) scripts/components/seasonmanager_pork.lua:1776: attempt to compare nil with number
LUA ERROR stack traceback:
    scripts/components/seasonmanager_pork.lua:1776 in (method) DoLightningStrike (Lua) <1768-1818>
    scripts/prefabs/thunderbird.lua:35 in (field) fn (Lua) <31-36>
    scripts/scheduler.lua:195 in (method) OnTick (Lua) <169-226>
    scripts/scheduler.lua:402 in (global) RunScheduler (Lua) <400-408>
    scripts/update.lua:105 in () ? (Lua) <90-191>
	
scripts/frontend.lua(738,1) SCRIPT ERROR! Showing error screen