If the End hotkey is pressed to move a mesh down to align on top of another mesh/landscape and a camera blocking volume is below it, the trace down will register a hit on the camera blocking volume and place itself on top of the camera blocking volume.
Note: The camera blocking volume is set to overlap but not block static meshes, with normal blocking volumes setting world static and dynamic to overlap causes the mesh to move down to the mesh below the blocking volume when End key is pressed.
1. Open Editor (any project)
2. Create a camera blocking volume, place over the floor mesh
3. Create a static mesh (any), move above the camera blocking volume. Leave ~100uu of space so it can visibly move downward
4. With the static mesh selected, press "End" key
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-16135 in the post.