I am occasionally seeing a game hang of about 10 seconds followed by the following LUA error. It is happening to me in vSS Loki HM while tanking. I've seen it twice now in the past week.

EsoUI/Ingame/InteractWindow/Keyboard/InteractWindow_Keyboard.lua:164: attempt to index a nil value
stack traceback:
EsoUI/Ingame/InteractWindow/Keyboard/InteractWindow_Keyboard.lua:164: in function 'ZO_Interaction:PopulateChatterOption'
|caaaaaa<Locals> self = [table:1]{sceneName = "interact", questRewardName = "ZO_QuestReward", optionCount = 2, chatterOptionName = "ZO_ChatterOption", currencyTemplateName = "ZO_CurrencyTemplate"}, controlID = 11, optionIndex = 11, optionText = "", optionType = 0, optionalArg = 0, isImportant = F, chosenBefore = F, importantOptions = [table:2]{} </Locals>|r
EsoUI/Ingame/InteractWindow/InteractWindow_Shared.lua:396: in function 'ZO_SharedInteraction:PopulateChatterOptions'
|caaaaaa<Locals> self = [table:1], optionCount = 100665191, backToTOCOption = F, importantOptions = [table:2], i = 11, optionString = "", optionType = 0, optionalArg = 0, isImportant = F, chosenBefore = F, controlID = 11 </Locals>|r
EsoUI/Ingame/InteractWindow/Keyboard/InteractWindow_Keyboard.lua:219: in function 'ZO_Interaction:UpdateChatterOptions'
|caaaaaa<Locals> self = [table:1], optionCount = 100665191, backToTOCOption = F </Locals>|r
EsoUI/Ingame/InteractWindow/InteractWindow_Shared.lua:118: in function 'OnChatterBegin'
|caaaaaa<Locals> _ = 131072, chatterOptionCount = 100665191 </Locals>|r
EsoUI/Ingame/InteractWindow/InteractWindow_Shared.lua:74: in function '(anonymous)'
|caaaaaa<Locals> obj = [table:1] </Locals>|