[iOS] CMake shader handling fails

qt_add_shaders(duck_track "shaders"
    PREFIX
        "/"
    FILES
        "shadow.frag"
)

-- Using Qt bundled PCRE2.
-- Could NOT find EGL (missing: EGL_INCLUDE_DIR HAVE_EGL EGL_LIBRARY)  
-- Using Qt bundled PNG.
-- Using Qt bundled Harfbuzz.
-- Using Qt bundled Freetype.
-- Could NOT find EGL (missing: EGL_INCLUDE_DIR HAVE_EGL EGL_LIBRARY)  
-- Using Qt bundled Jpeg.
shadow.frag -> shadow.frag.qsb exposed as ://shadow.frag.qsb
-- Configuring done
-- Generating done
CMake Error in duck/track/CMakeLists.txt:
  The custom command generating

    /Users/prcs1076/build-localist-Qt_6_3_0_for_iOS/duck/track/.qsb/shadow.frag.qsb

  is attached to multiple targets:

    duck_track_other_files
    duck_track_resources_1

  but none of these is a common dependency of the other(s).  This is not
  allowed by the Xcode "new build system".

CMake Generate step failed.  Build files cannot be regenerated correctly.
CMake process exited with exit code 1.