What steps will reproduce the problem?
1. Started quest with Pet Trainer Robert Craig, in Stormheim

What is the expected output? What do you see instead?
This patch seems to have really done something crazy, because a LOT of addons are throwing errors or glitching out, so I don't know how much of this is Chatter, only that Chatter was the one that threw up the error. When I entered pet battle combat with Robert Craig, the pet battle interface was blank, with no attacks or the option to leave the battle. I had to log out to exit the interface. I do know that I did the pet battle with the trainer in Dalaran earlier today, BEFORE I updated Chatter(something I just did before I signed on this time), and didn't have this problem, but that may be due to something unrelated, like the zone or what have you.

What version of the product are you using?
1.5.2

Do you have an error log of what happened?

I do! Here you go:

Date: 2016-10-25 18:35:20
ID: 8
Error occured in: Global
Count: 1
Message: ..\AddOns\Chatter\Modules\AutoPopup.lua line 40:
attempt to index local 'info' (a nil value)
Debug:
Chatter\Modules\AutoPopup.lua:40: AlwaysDecorate()
Chatter\Chatter.lua:196:
Chatter\Chatter.lua:183
(tail call): ?
...AddOns\Blizzard_PetBattleUI\Blizzard_PetBattleUI.lua:149: PetBattleFrame_Display()
...AddOns\Blizzard_PetBattleUI\Blizzard_PetBattleUI.lua:95:
...AddOns\Blizzard_PetBattleUI\Blizzard_PetBattleUI.lua:92
Locals:

AddOns:
Swatter, v7.1.5675 (TasmanianThylacine)
AckisRecipeList, v7.0.3.8
Altoholic, vr171
ArkInventory, v30715
ArkInventoryRules, v10003
ArkInventoryRulesExample, v10000
AucAdvanced, v7.1.5675 (TasmanianThylacine)
AucFilterBasic, v7.1.5675 (TasmanianThylacine)
AucFilterOutlier, v7.1.5675.5459(7.1/embedded)
AucMatchUndercut, v7.1.5675.5585(7.1/embedded)
AucStatHistogram, v7.1.5675 (TasmanianThylacine)
AucStatiLevel, v7.1.5675 (TasmanianThylacine)
AucStatPurchased, v7.1.5675 (TasmanianThylacine)
AucStatSales, v7.1.5675.5598(7.1/embedded)
AucStatSimple, v7.1.5675 (TasmanianThylacine)
AucStatStdDev, v7.1.5675 (TasmanianThylacine)
AucStatWOWEcon, v7.1.5675.5613(7.1/embedded)
AucUtilAHWindowControl, v7.1.5675.5575(7.1/embedded)
AucUtilAppraiser, v7.1.5675.5666(7.1/embedded)
AucUtilAskPrice, v7.1.5675.5599(7.1/embedded)
AucUtilAutoMagic, v7.1.5675.5587(7.1/embedded)
AucUtilCompactUI, v7.1.5675.5629(7.1/embedded)
AucUtilEasyBuyout, v7.1.5675.5576(7.1/embedded)
AucUtilFixAH, v7.1.5675 (TasmanianThylacine)
AucUtilItemSuggest, v7.1.5675.5651(7.1/embedded)
AucUtilPriceLevel, v7.1.5675.5633(7.1/embedded)
AucUtilScanButton, v7.1.5675.5631(7.1/embedded)
AucUtilScanFinish, v7.1.5675.5588(7.1/embedded)
AucUtilScanProgress, v7.1.5675.4979(7.1/embedded)
AucUtilScanStart, v7.1.5675.5347(7.1/embedded)
AucUtilSearchUI, v7.1.5675.5672(7.1/embedded)
AucUtilSimpleAuction, v7.1.5675.5654(7.1/embedded)
AucUtilVendMarkup, v7.1.5675.4828(7.1/embedded)
Babylonian, v5.1.DEV.332(/embedded)
CaerdonWardrobe, vv0.38.0
CaerdonWardrobeArkinventory, vv0.3.0
Cellular, v6.2.001
Chatter, v1.5.2
Chinchilla, vv2.8.1
ClassicQuestLog, v1.2.6
Configator, v5.1.DEV.406(/embedded)
DataStore, vr59
DataStoreAchievements, vr42
DataStoreAgenda, vr23
DataStoreAuctions, v6.0.001
DataStoreCharacters, vr36
DataStoreContainers, vr53
DataStoreCrafts, vr73
DataStoreCurrencies, vr31
DataStoreGarrisons, vr16
DataStoreInventory, vr46
DataStoreMails, vr46
DataStorePets, vr39
DataStoreQuests, vr36
DataStoreReputations, vr37
DataStoreSpells, vr27
DataStoreStats, vr26
DataStoreTalents, vr54
DBMCore, v
DBMDefaultSkin, v
DBMStatusBarTimers, v
DebugLib, v5.1.DEV.337(/embedded)
Decursive, v2.7.4.7
Dominos, v7.1.1
DominosActionSets, v
DominosCast, v
DominosEncounter, v
DominosProgress, v
DominosRoll, v
GatherMate2, v1.37.1
Grid, v7.0.3.3
GridManaBars, v1.11
HandyNotes, vv1.4.9
HandyNotesLegionRaresTreasures, v1.01a
Informant, v7.1.5675 (TasmanianThylacine)
LibExtraTip, v5.12.DEV.412(/embedded)
Mapster, v1.7.2
Masque, v7.0.1
MasqueApathy, v7.0.0
MasqueCleanUI, v7.1
MasqueSimpleSquare, v7.0.3.0
MasterPlanA, vA
MikScrollingBattleText, v5.7.146
MinimapButtonFrame, v3.1.10e
MinimapButtonFrameSkinPack, v3.0.1b
MogIt, v3.6.5
MogItCloth, v3.6.5
MogItCosmetic, v3.6.5
MogItLeather, v3.6.5
MogItMail, v3.6.5
MogItOneHanded, v3.6.5
MogItOther, v3.6.5
MogItPlate, v3.6.5
MogItRanged, v3.6.5
MogItTwoHanded, v3.6.5
mOnArsWardrobeHelper, v1.16.2
MyMedia, vv1.0
NPCScan, v7.1.0.1
Paste, v1.4.9
PersonalLootHelper, v1.16
PitBull4, vv4.0.10
PitBull4AltPowerBar, vv4.0.10
PitBull4ArtifactPowerBar, vv4.0.10
PitBull4Aura, vv4.0.10
PitBull4Background, vv4.0.10
PitBull4BattlePet, vv4.0.10
PitBull4BlankSpace, vv4.0.10
PitBull4Border, vv4.0.10
PitBull4CastBar, vv4.0.10
PitBull4CastBarLatency, vv4.0.10
PitBull4CombatFader, vv4.0.10
PitBull4CombatIcon, vv4.0.10
PitBull4ComboPoints, vv4.0.10
PitBull4HealthBar, vv4.0.10
PitBull4HideBlizzard, vv4.0.10
PitBull4HostilityFader, vv4.0.10
PitBull4LeaderIcon, vv4.0.10
PitBull4LuaTexts, vv4.0.10
PitBull4MasterLooterIcon, vv4.0.10
PitBull4PhaseIcon, vv4.0.10
PitBull4Portrait, vv4.0.10
PitBull4PowerBar, vv4.0.10
PitBull4PvPIcon, vv4.0.10
PitBull4QuestIcon, vv4.0.10
PitBull4RaidTargetIcon, vv4.0.10
PitBull4RangeFader, vv4.0.10
PitBull4ReadyCheckIcon, vv4.0.10
PitBull4RestIcon, vv4.0.10
PitBull4RoleIcon, vv4.0.10
PitBull4VisualHeal, vv4.0.10
PitBull4VoiceIcon, vv4.0.10
Postal, vv3.5.8
Raven, vr376
Recount, vv7.0.3k release
RegularTab, v
Rematch, v4.5.6
ReputationSorter, v
Stubby, v7.1.5675 (TasmanianThylacine)
TellMeWhen, v8.2.0
TidyPlates, v6.18.10
TidyPlatesGraphite, v
TidyPlatesGrey, v
TidyPlatesNeon, v
TidyPlatesQuatre, v
TidyPlatesHub, v
TidyPlatesWidgets, v
TipHelper, v5.12.DEV.405(/embedded)
TipTac, v16.08.30
TipTacItemRef, v16.08.30
TipTacTalents, v16.07.21
TomTom, vv70000-1.1.0
WorldQuestTracker, v
BlizRuntimeLib_enUS v7.1.0.70100 <none>
(ck=1234)

Please provide any additional information below.
Disabling Chatter DID bring the pet battle UI back, without any other changes to other addons.

Anyway, thank you for all your hard work, and good luck with swatting all this craziness! I feel like this patch has addon creators tearing their hair out. I can't process how you guys manage to go through all of this just for the good of the community -- you really are awesome folks.