After defeating the Mist Spirit, you get the following error

The actual error text is:
Error: <<run>>: bad evaluation: can't access property "delete", setup.uniquetravelevents is undefined
<<run setup.uniquetravelevents.delete("mistspirit")>>
Error: <<run>>: bad evaluation: can't access property "delete", setup.exploreunique is undefined
<<run setup.exploreunique.delete("mistspiritinfo")>>
Error: <<set>>: bad evaluation: can't access property "push", setup.greatdeeds is undefined
<<set setup.greatdeeds.push(setup.defeatmistspirit)>>
Error: <<set>>: bad evaluation: can't access property "push", setup.greatdeedsrewards is undefined
<<set setup.greatdeedsrewards.push(setup.defeatmistspirit)>>