I have a test landscape and I am not seeing the issue you showed in the example video. Are you able to reproduce this issue in a blank project with some steps for me to follow?
I know we made some changes to the Landscape LOD visualizers as well as the HLOD system, which is being used for Paragon. Take a read through the 4.11 Release Notes to see if there is anything in there you spot that could be the culprit.