Fix Regression: null UWorld deref in CesiumGaussianSplatSubsystem::Tick

CHANGES.md

@@ -7,6 +7,7 @@
 - Added missing includes that introduced compilation failures when building the plugin from source against UE 5.7's bundled clang 20.1.8 toolchain (introduced in v2.25.0 by #1685; binary plugin users were unaffected).
 - Fixed the case where glTF line primitives caused excessive log spam due to Chaos attempting to generate physics bodies for small non-triangle meshes.
 - Fixed an incorrect transform that reversed the appearance of data in box voxel tilesets.
+- Fixed a crash in `UCesiumGaussianSplatSubsystem::Tick` when `GetPrimaryWorld()` returns `nullptr` (e.g. between PIE shutdown and Standalone-Game launch, or on nDisplay secondary nodes during world bind-up). Restores the validity check ordering that shipped in v2.24.1 and was inadvertently inverted in v2.26.0 (#1841).
 
 ### v2.26.0 - 2026-05-01
 

Source/CesiumRuntime/Private/CesiumGaussianSplatSubsystem.cpp

@@ -229,13 +229,6 @@ void UCesiumGaussianSplatSubsystem::Tick(float DeltaTime) {
   }
 
   UWorld* pWorld = GetPrimaryWorld();
-  // Gaussian splats are purely visual, so we don't need to initialize them if
-  // we can't render anything. Besides, the Niagara component will fail to
-  // spawn if either of these conditions are false (they are checked in
-  // UNiagaraFunctionLibrary::CreateNiagaraSystem).
-  if (!FApp::CanEverRender() || pWorld->IsNetMode(NM_DedicatedServer)) {
-    return;
-  }
 
   if (!IsValid(pWorld)) {
     if (IsValid(this->_pNiagaraActor)) {
@@ -245,6 +238,14 @@ void UCesiumGaussianSplatSubsystem::Tick(float DeltaTime) {
     return;
   }
 
+  // Gaussian splats are purely visual, so we don't need to initialize them if
+  // we can't render anything. Besides, the Niagara component will fail to
+  // spawn if either of these conditions are false (they are checked in
+  // UNiagaraFunctionLibrary::CreateNiagaraSystem).
+  if (!FApp::CanEverRender() || pWorld->IsNetMode(NM_DedicatedServer)) {
+    return;
+  }
+
   if (!IsValid(this->_pNiagaraActor) || pWorld != this->_pLastCreatedWorld) {
     this->initializeForWorld(*pWorld);
   }