When a landscape is set up to use runtime virtual texturing.
If it uses a material that writes to a runtime virtual texture and has tessellation enabled.
Then we see a crash and the log reports:
Shader expected a uniform buffer of struct type LandscapeContinuousLODParameters at slot 3 but got null instead. Rendering code needs to set a valid uniform buffer for this slot.
This was reported in:
Open TM-RuntimeVirtualTextures map in QAGame project
Open Landscape_RVT_Mat material
Set the D3D11Tessellation property on the material to "Flat Tessellation"
Observe the crash
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-88565 in the post.