Master crash

Server running version 388775 had Master shard crashing with this error a few minutes ago:

[11:08:20]: [string "scripts/prefabs/wintersfeastbuff.lua"]:26: attempt to perform arithmetic on a nil value
LUA ERROR stack traceback:
scripts/prefabs/wintersfeastbuff.lua:26 in (upvalue) CalcIntensity (Lua) <25-27>
   inst = 459233 - wintersfeastbuff (valid:false)
scripts/prefabs/wintersfeastbuff.lua:94 in (field) addeffectbonusfn (Lua) <76-95>
   inst = 459233 - wintersfeastbuff (valid:false)
   num_feasters = 1
   num_foodtypes = 0
   num_totalfood = 0
   timeleft = nil
   score = 0
   bonus = 0
scripts/components/feasts.lua:76 in (upvalue) ApplyFeastBuff (Lua) <57-78>
   feaster = 458184 - wolfgang (valid:false)
   tables = table: 0x1715d380
   totalfeasters = 1
   foods = table: 0x1caefec0
   totalfood = 0
   differentfoodtypes = 0
   buff = 459233 - wintersfeastbuff (valid:false)
scripts/components/feasts.lua:100 in (field) fn (Lua) <80-123>
   activegroups = table: 0x1f3732e0
   group = 3
   feasters = table: 0x26838640
   i = 1
   feaster = 458184 - wolfgang (valid:false)
scripts/scheduler.lua:177 in (method) OnTick (Lua) <155-207>
   self =
      running = table: 0x270a54f0
      waitingfortick = table: 0x21eda040
      tasks = table: 0x28390f10
      waking = table: 0x21ff6600
      attime = table: 0xceb1f00
      hibernating = table: 0x2d2acd20
   tick = 1518839
   k = PERIODIC 100025: 0.333333
   v = true
   already_dead = nil
scripts/scheduler.lua:371 in (global) RunScheduler (Lua) <369-377>
   tick = 1518839
scripts/update.lua:180 in () ? (Lua) <159-238>
   dt = 0.033333335071802
   tick = 1518839
   i = 1518839
[11:08:20]: [string "scripts/prefabs/wintersfeastbuff.lua"]:26: attempt to perform arithmetic on a nil value
LUA ERROR stack traceback:
    scripts/prefabs/wintersfeastbuff.lua:26 in (upvalue) CalcIntensity (Lua) <25-27>
    scripts/prefabs/wintersfeastbuff.lua:94 in (field) addeffectbonusfn (Lua) <76-95>
    scripts/components/feasts.lua:76 in (upvalue) ApplyFeastBuff (Lua) <57-78>
    scripts/components/feasts.lua:100 in (field) fn (Lua) <80-123>
    scripts/scheduler.lua:177 in (method) OnTick (Lua) <155-207>
    scripts/scheduler.lua:371 in (global) RunScheduler (Lua) <369-377>
    scripts/update.lua:180 in () ? (Lua) <159-238>
    
[11:08:20]: Warning: Widget:SetFocusFromChild is happening on a widget outside of the screen/widget hierachy. This will cause focus moves to fail. Is     ScriptErrorWidget    not a screen?    
[11:08:20]: stack traceback:
    scripts/widgets/widget.lua:605 in (method) SetFocusFromChild (Lua) <602-627>
    scripts/widgets/widget.lua:624 in (method) SetFocusFromChild (Lua) <602-627>
    scripts/widgets/widget.lua:624 in (method) SetFocusFromChild (Lua) <602-627>
    scripts/widgets/widget.lua:656 in (method) SetFocus (Lua) <629-665>
    scripts/widgets/menu.lua:83 in (method) SetFocus (Lua) <74-85>
    scripts/widgets/scripterrorwidget.lua:109 in (method) OnUpdate (Lua) <102-119>
    scripts/update.lua:90 in () ? (Lua) <33-129>   

oh, and for some reason I see a lot of lines like:

[11:08:19]: Stale Component Reference: GUID 459233, scripts/prefabs/wintersfeastbuff.lua:94
[11:08:19]: Stale Component Reference: GUID 459233, scripts/prefabs/wintersfeastbuff.lua:94
[11:08:19]: Stale Component Reference: GUID 459233, scripts/prefabs/wintersfeastbuff.lua:94
[11:08:20]: Stale Component Reference: GUID 459233, scripts/prefabs/wintersfeastbuff.lua:94
[11:08:20]: Stale Component Reference: GUID 459233, scripts/prefabs/wintersfeastbuff.lua:94