How do you avoid duplicating include files into the /debug/include directory with CMake?

Question

I am trying to create a port for vcpkg of a header only library. When installing the port the configuration and installation work correctly, but in the post-build validation step I get the error

warning: Include files should not be duplicated into the /debug/include directory.
If this cannot be disabled in the project cmake, use
file(REMOVE_RECURSE "${CURRENT_PACKAGES_DIR}/debug/include")

The guides I've seen all add the file command in the portfile.cmake file instead of fixing the CMakeLists.txt, but I'd rather do the right thing and fix the CMakeLists.txt file. Only, I don't know how.

The project structure looks like (skipping some unrelated files):

hlib/
+ include/
| + hlib/
|   + hlib.hpp
+ CMakeListst.txt

The CMakeLists.txt file for the project looks like:

cmake_minimum_required(VERSION 3.20)

project(hlib
  VERSION 0.1.0
  LANGUAGES CXX)

include(GNUInstallDirs)

if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
  include(CTest)
endif()

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

add_library(hlib INTERFACE)
target_include_directories(
  hlib
  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)

install(TARGETS hlib
        EXPORT hlib_Targets
        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})

include(CMakePackageConfigHelpers)
write_basic_package_version_file("hlibConfigVersion.cmake"
                                 VERSION ${PROJECT_VERSION}
                                 COMPATIBILITY SameMajorVersion)

configure_package_config_file(
  "${PROJECT_SOURCE_DIR}/cmake/hlibConfig.cmake.in"
  "${PROJECT_BINARY_DIR}/hlibConfig.cmake"
  INSTALL_DESTINATION
  ${CMAKE_INSTALL_DATAROOTDIR}/hlib/cmake)

install(EXPORT hlib_Targets
        FILE hlibTargets.cmake
        NAMESPACE hlib::
        DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/hlib/cmake)

install(FILES "${PROJECT_BINARY_DIR}/hlibConfig.cmake"
              "${PROJECT_BINARY_DIR}/hlibConfigVersion.cmake"
        DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/hlib/cmake)

install(DIRECTORY ${PROJECT_SOURCE_DIR}/include/hlib DESTINATION include)

if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND BUILD_TESTING)
  add_subdirectory(tests)
endif()

What would I need to change so that include files are not duplicated into the /debug/include directory?