Switching between SM5 and ES31 views in the Editor shows some small variation in landscape heights.
ES31 heights are stored in the vertex with some slight lossy compression so subtle variation can happen. But the situation regressed in engine release 4.25.
Load the attached small project.
Look at the intersection between the cube actor and the landscape.
Switch between ES31 and SM5 and observe the change.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-93929 in the post.