Dedicated Server and World Partitioning (MissingLevelPackage)

I can confirm this fixed the issue for me in 5.4.4. Thanks so much! I believe this might worthwhile for a PR; are you interested in making the PR or shall I @alexdjq. Specifically here are the changes you need:

--- a/Engine/Source/Runtime/Engine/Private/LevelUtils.cpp
+++ b/Engine/Source/Runtime/Engine/Private/LevelUtils.cpp
@@ -79,6 +79,17 @@ ULevelStreaming* FLevelUtils::FindStreamingLevel(const ULevel* Level)
        return ULevelStreaming::FindStreamingLevel(Level);
 }

+static bool CompareRightMostSubPath(const FString& Lhs, const FString& Rhs)
+{
+       int32 LastSlashIndex = 0;
+       if (!Lhs.FindLastChar('/', LastSlashIndex))
+       {
+               return false;
+       }
+       int32 SubPathLength = Lhs.Len() - LastSlashIndex;
+       return Lhs.Right(SubPathLength) == Rhs.Right(SubPathLength);
+}
+
 ULevelStreaming* FLevelUtils::FindStreamingLevel(UWorld* InWorld, const FName PackageName)
 {
        ULevelStreaming* MatchingLevel = NULL;
@@ -91,6 +102,11 @@ ULevelStreaming* FLevelUtils::FindStreamingLevel(UWorld* InWorld, const FName Pa
                                MatchingLevel = CurStreamingLevel;
                                break;
                        }
+                       if (CompareRightMostSubPath(PackageName.ToString(), CurStreamingLevel->GetWorldAssetPackageName()))
+                       {
+                               MatchingLevel = CurStreamingLevel;
+                               break;
+                       }
                }
        }
        return MatchingLevel;

Note, 5.4.x (fixed in 5.5.0) also has a separate issue with connecting PIE clients to a packaged DS when using ACharacter: Unreal 5.4 problem with a packaged game! Server spawns the character and client disconnecting with 'Failed to load package' error. - #10 by NV_gnoowik