Qt6WebEngineCoreDeploySupport fails when generating RPM

I have a test project which uses qt_generate_deploy_app_script to deploy an executable that depends on Qt::WebEngineWidgets. When generating the rpm via cpack -G RPM i get the following error:

CMake Error at /opt/Qt/6.8.2/gcc_64/lib/cmake/Qt6WebEngineCore/Qt6WebEngineCoreDeploySupport.cmake:87 (file):
  file does not exist:

    /tmp/test_webengine/build/_CPack_Packages/Linux/RPM/test_webengine-0.1-Linux/opt/test_webengine/libexec/QtWebEngineProcess

That is because at Qt6WebEngineCoreDeploySupport.cmake:83 the call to file(INSTALL ...) copies the QtWebEngineProcess into

/tmp/test_webengine/build/_CPack_Packages/Linux/RPM/test_webengine-0.1-Linux/tmp/test_webengine/build/_CPack_Packages/Linux/RPM/test_webengine-0.1-Linux/opt/test_webengine/libexec/QtWebEngineProcess

instead of

/tmp/test_webengine/build/_CPack_Packages/Linux/RPM/test_webengine-0.1-Linux/opt/test_webengine/libexec/QtWebEngineProcess

Replacing file(INSTALL ...) with file(COPY ...) in Qt6WebEngineCoreDeploySupport.cmake the RPM generates as expected.

I'm not even sure it's a Qt bug to be honest, but from the looks of it the deploy script is not honoring the CMAKE_INSTALL_PREFIX.

Another thing I tried is adding install(CODE "set(QT_DEPLOY_PREFIX \"\${CMAKE_INSTALL_PREFIX}\")"), this copies the QtWebEngineProcess in the correct path but then the call to file(CHMOD ...) fails.

The CMake version I'm using is 3.29.3.