Hello everyone,
since updating my project from UE5.3 to
UE5.7, I’m experiencing a reproducible crash in the packaged build using DirectX12.
When packaging with DirectX11, the issue does not occur — everything runs normally.
As soon as I enter a specific region in the game, the build crashes with the following error:
Code
Assertion failed: (Index >= 0) & (Index < ArrayNum)
File: Engine\Source\Runtime\Core\Public\Containers\Array.h
Line: 1095
Array index out of bounds: 1 into an array of size 1
The region only contains simple Blueprint objects, such as:
-
Door Blueprints
-
Road markings
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Construction scripts
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A barrier gate
All of these Blueprints also exist in other areas of the map and work without any issues there.
The crash happens only in this one region and only under DX12.
What I have checked so far
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Inspected all related Blueprints for array access → no dynamic arrays, no ForEach loops, no index operations.
-
Tested the same doors/barrier in other locations → works fine.
-
Rebuilt the entire region → crash persists.
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Rebuilt lighting → no change.
-
Packaged with DX11 → no crash.
-
Packaged with DX12 → crash is 100% reproducible.
My suspicion
Since the issue only started after updating to UE5.7 and only occurs under DX12, I suspect:
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an engine regression in 5.7, possibly related to Blueprint Construction Scripts or Instanced Static Meshes
-
or an internal array access in an engine subsystem triggered only under DX12 (Nanite, Lumen, HLOD, streaming, navigation, etc.)
Question to Epic / the community
Has anyone experienced similar issues since updating to UE5.7 + DX12?
Are there any known problems where DX12 triggers array out‑of‑bounds errors in packaged builds, even when the Blueprints themselves do not use arrays?
I can provide:
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an isolated test region
-
logs / crash dumps
-
a stripped‑down test project
Thanks in advance for any help!
Himiko
