Crash in ISM on Async Gathering

Development Programming & Scripting
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void UInstancedStaticMeshComponent::GetNavigationPerInstanceTransforms(const FBox& AreaBox, TArray<FTransform>& InstanceData) const { const FBox InstanceBounds = GetInstanceNavigationBounds(); if (InstanceBounds.IsValid) { const FBox LocalAreaBox = AreaBox.InverseTransformBy(GetComponentTransform()); for (const auto& InstancedData : PerInstanceSMData) { const FTransform InstanceToComponent(InstancedData.Transform); if (!InstanceToComponent.GetScale3D().IsZero()) { const FBoxSphereBounds TransformedInstanceBounds = InstanceBounds.TransformBy(InstancedData.Transform); if (LocalAreaBox.Intersect(TransformedInstanceBounds.GetBox())) { InstanceData.Add(InstanceToComponent*GetComponentTransform()); } } } } }this can crash if the underlying data is modified on the game thread

<CallStack>DominanceTOE!UE::Math::TTransform&lt;double&gt;::SetFromMatrix() [C:\Builds\DominanceBuild\Engine\Source\Runtime\Core\Public\Math\TransformVectorized.h:1250]

DominanceTOE!UInstancedStaticMeshComponent::GetNavigationPerInstanceTransforms() [C:\Builds\DominanceBuild\Engine\Source\Runtime\Engine\Private\InstancedStaticMesh.cpp:5461]

DominanceTOE!TBaseUObjectMethodDelegateInstance&lt;1,UInstancedStaticMeshComponent const ,void __cdecl(UE::Math::TBox&lt;double&gt; const &amp;,TArray&lt;UE::Math::TTransform&lt;double&gt;,TSizedDefaultAllocator&lt;32&gt; &gt; &amp;),FDefaultDelegateUserPolicy&gt;::Execute() [C:\Builds\DominanceBuild\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:651]

DominanceTOE!FRecastTileGenerator::AppendModifier() [C:\Builds\DominanceBuild\Engine\Source\Runtime\NavigationSystem\Private\NavMesh\RecastNavMeshGenerator.cpp:2486]

DominanceTOE!FRecastTileGenerator::GatherNavigationDataGeometry()

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Steps to Reproduce
Update isms randomly whilst nav is generating

3

Do you happen to have the callstacks for both the game thread and worker thread? Or the minidump file? Is this a frequent crash or one that happens <25% of the time?

-James