Nanite objects disappear when switching RHI from DX12 to Vulkan (UE5.6, SM5)

I’m currently using UE5.6.
In the Windows Editor / Standalone Game, when I switch the RHI from DX12 to Vulkan with the feature level set to SM5, I notice that Nanite objects are no longer visible — even something as simple as a Nanite cube won’t show up.

After some quick investigation, it seems that InstanceHierarchyChunkCulling is culling it.
However, I don’t understand why this happens.

Has anyone else encountered a similar issue?