diff --git a/Dalamud/Game/Network/Internal/NetworkHandlers.cs b/Dalamud/Game/Network/Internal/NetworkHandlers.cs
index 9d552b519..ef8090d1c 100644
--- a/Dalamud/Game/Network/Internal/NetworkHandlers.cs
+++ b/Dalamud/Game/Network/Internal/NetworkHandlers.cs
@@ -2,8 +2,8 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Reactive.Linq;
-using System.Reactive.Subjects;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 
@@ -62,10 +62,7 @@ internal class NetworkHandlers : IDisposable, IServiceType
             }
 
             gameNetwork.NetworkMessage += Observe;
-            return () =>
-            {
-                gameNetwork.NetworkMessage -= Observe;
-            };
+            return () => { gameNetwork.NetworkMessage -= Observe; };
         });
 
         this.handleMarketBoardItemRequest = this.HandleMarketBoardItemRequest();
@@ -174,17 +171,8 @@ internal class NetworkHandlers : IDisposable, IServiceType
     private IObservable<List<MarketBoardCurrentOfferings.MarketBoardItemListing>> OnMarketBoardListingsBatch(
         IObservable<MarketBoardItemRequest> start)
     {
-        var startShared = start.Publish().RefCount();
         var offeringsObservable = this.OnMarketBoardOfferings().Publish().RefCount();
 
-        void LogStartObserved(MarketBoardItemRequest request)
-        {
-            Log.Verbose(
-                "Observed start of request for item#{CatalogId} with {NumListings} expected listings",
-                request.CatalogId,
-                request.AmountToArrive);
-        }
-
         void LogEndObserved(MarketBoardCurrentOfferings offerings)
         {
             Log.Verbose(
@@ -204,6 +192,7 @@ internal class NetworkHandlers : IDisposable, IServiceType
         {
             var totalPackets = Convert.ToInt32(Math.Ceiling((double)request.AmountToArrive / 10));
             return offeringsObservable
+                   .Where(offerings => offerings.ItemListings.All(l => l.CatalogId == request.CatalogId))
                    .Skip(totalPackets - 1)
                    .Do(LogEndObserved);
         }
@@ -213,7 +202,7 @@ internal class NetworkHandlers : IDisposable, IServiceType
         // packets, and then flatten them to the listings themselves.
         return offeringsObservable
                .Do(LogOfferingsObserved)
-               .Window(startShared.Where(request => request.Ok).Do(LogStartObserved), UntilBatchEnd)
+               .Window(start, UntilBatchEnd)
                .SelectMany(
                    o => o.Aggregate(
                        new List<MarketBoardCurrentOfferings.MarketBoardItemListing>(),
@@ -224,17 +213,59 @@ internal class NetworkHandlers : IDisposable, IServiceType
                        }));
     }
 
-    private IObservable<List<MarketBoardHistory.MarketBoardHistoryListing>> OnMarketBoardSalesBatch()
+    private IObservable<List<MarketBoardHistory.MarketBoardHistoryListing>> OnMarketBoardSalesBatch(
+        IObservable<MarketBoardItemRequest> start)
     {
-        return this.OnMarketBoardHistory().Select(history => history.HistoryListings);
+        var historyObservable = this.OnMarketBoardHistory().Publish().RefCount();
+
+        void LogHistoryObserved(MarketBoardHistory history)
+        {
+            Log.Verbose(
+                "Observed history for item {CatalogId} with {NumSales} sales",
+                history.CatalogId,
+                history.HistoryListings.Count);
+        }
+
+        IObservable<MarketBoardHistory> UntilBatchEnd(MarketBoardItemRequest request)
+        {
+            return historyObservable
+                   .Where(history => history.CatalogId == request.CatalogId)
+                   .Take(1);
+        }
+
+        // When a start packet is observed, begin observing a window of history packets.
+        // We should only get one packet, which the window closing function ensures.
+        // This packet is flattened to its sale entries and emitted.
+        return historyObservable
+               .Do(LogHistoryObserved)
+               .Window(start, UntilBatchEnd)
+               .SelectMany(
+                   o => o.Aggregate(
+                       new List<MarketBoardHistory.MarketBoardHistoryListing>(),
+                       (agg, next) =>
+                       {
+                           agg.AddRange(next.HistoryListings);
+                           return agg;
+                       }));
     }
 
     private IDisposable HandleMarketBoardItemRequest()
     {
-        var startObservable = this.OnMarketBoardItemRequestStart();
+        void LogStartObserved(MarketBoardItemRequest request)
+        {
+            Log.Verbose(
+                "Observed start of request for item#{CatalogId} with {NumListings} expected listings",
+                request.CatalogId,
+                request.AmountToArrive);
+        }
+
+        var startObservable = this.OnMarketBoardItemRequestStart()
+                                  .Where(request => request.Ok).Do(LogStartObserved)
+                                  .Publish()
+                                  .RefCount();
         return Observable.When(
                              startObservable
-                                 .And(this.OnMarketBoardSalesBatch())
+                                 .And(this.OnMarketBoardSalesBatch(startObservable))
                                  .And(this.OnMarketBoardListingsBatch(startObservable))
                                  .Then((request, sales, listings) => (request, sales, listings)))
                          .Where(this.ShouldUpload)
@@ -252,6 +283,18 @@ internal class NetworkHandlers : IDisposable, IServiceType
         ICollection<MarketBoardHistory.MarketBoardHistoryListing> sales,
         ICollection<MarketBoardCurrentOfferings.MarketBoardItemListing> listings)
     {
+        if (listings.Count != request.AmountToArrive)
+        {
+            Log.Error("Wrong number of Market Board listings received for request: {ListingsCount} != {RequestAmountToArrive} item#{RequestCatalogId}", listings.Count, request.AmountToArrive, request.CatalogId);
+            return;
+        }
+
+        if (listings.Any(listing => listing.CatalogId != request.CatalogId))
+        {
+            Log.Error("Received listings with mismatched item IDs for item#{RequestCatalogId}", request.CatalogId);
+            return;
+        }
+
         Log.Verbose(
             "Market Board request resolved, starting upload: item#{CatalogId} listings#{ListingsObserved} sales#{SalesObserved}",
             request.CatalogId,