Project structure no longer generated with CMake 3.15 or higher

Project structure in QtCreator no longer shows the directory structure, instead it only shows files under "Header Files" and "Source Files" tags.
This used to work with older CMake versions, eg. CMake 3.11.4
See the attached pictures of the project structure on disk and visible structure in QtCreator with different CMake versions.

Steps:

• Install CMake 3.15 or higher
• Configure QtCreator's Qt Kit to use the installed CMake version
• Load the attached testp.tar.gz as a CMake project
  Outcome:
• The project view does not show the directory structure (as can be seen in using_cmake-3.15_or_3.16.png)
  Expected:
• The project view shows the directory structure (as can be seen in using_cmake_3.11.4_or_lower.png )