Including both a subdirectory and its parent in CMake results in headers in parent directory getting omitted

Hello! I am currently developing a CMake project using a Docker container that requires including headers that resides in the following directory structure:

• includes
  • Header1.hh
  • Header2.hh
  • subdirectory
    • Header3.hh
    • Header4.hh

My CMakeLists.txt include the following statements (paths are actually populated using environment vairables retreived using find_package:

include_directories("/path/to/includes")
include_directories("/path/to/includes/subdirectory")

Unfortuantely this results in Header1.hh and Header2.hh not getting picked up. I inspected the local cache copied over located under ~/.cache/JetBrains/CLion2023.3/.docker/2023_3/Docker, all header files in the parent directory is omitted from this cache. 

I have tried altering the order of these two statements, to no avail.