这是一个在5.3.2上碰到的问题，不清楚更新一点的引擎还会不会有。 Build HLOD中如果Landscape参与了Build那么可能会出现 Build中断崩溃的情况。
这个在UDN上也能翻到对应的其他人的提问， https://udn.unrealengine.com/s/question/0D54z00009dZSD3CAO/engine-crashing-when-trying-to-build-hlods-in-53
崩溃的堆栈类似如下，主要是崩溃在ALandscapeProxy::ExportToRawMeshDataCopyNew()
[2023.09.18-00.39.57:482][222]LogWindows: Windows GetLastError: The operation completed successfully. (0)
[2023.09.18-00.40.04:668][222]LogWindows: Error: === Critical error: ===
[2023.09.18-00.40.04:668][222]LogWindows: Error:
[2023.09.18-00.40.04:668][222]LogWindows: Error: Assertion failed: Pair != nullptr [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Map.h] [Line: 671]
[2023.09.18-00.40.04:668][222]LogWindows: Error:
[2023.09.18-00.40.04:668][222]LogWindows: Error:
[2023.09.18-00.40.04:668][222]LogWindows: Error:
[2023.09.18-00.40.04:668][222]LogWindows: Error: [Callstack] 0x00007ff906e89cae UnrealEditor-Landscape.dll!ALandscapeProxy::ExportToRawMeshDataCopyNew() [D:\build\++UE5\Sync\Engine\Source\Runtime\Landscape\Private\LandscapeEdit.cpp:4187]
[2023.09.18-00.40.04:668][222]LogWindows: Error: [Callstack] 0x00007ff906e861ce UnrealEditor-Landscape.dll!ALandscapeProxy::ExportToRawMesh() [D:\build\++UE5\Sync\Engine\Source\Runtime\Landscape\Private\LandscapeEdit.cpp:3846]
[2023.09.18-00.40.04:668][222]LogWindows: Error: [Callstack] 0x00007ff906fb6872 UnrealEditor-Landscape.dll!ULandscapeHLODBuilder::Build()
经过我在git的历史里刨了半天以后，翻到一个可能修复了这个问题的提交，这个提交把ALandscapeProxy::ExportToRawMeshDataCopyNew()这个函数都给干没了。
Potential Fix: https://github.com/EpicGames/UnrealEngine/commit/b9b8d9517582d95f3693ad68dd3cfd1cb9417124
另外一个解决这个问题的方案是把设置 landscape.nanite.marchingsquaresvisibility = 0，可以绕开这个问题。