cmake/qsb fails to create the .qsb subdirectory

Tried Qt 6.8.0 Beta1 with my project: https://github.com/uwerat/qskinny

The build step fails with: Unable to create DEPFILE: '/opt/qskinny/build/qsk1/src/.qsb/arcshadow.vert.qsb.d'

The reason for the error is a missing subdirectory '.qsb', that is not created automatically. After creating the directory manually everything works fine.

( Might be fixed in the cmake rules or the qsb tool )

The corresponding lines in my 'build.make' file look like this:

src/.qsb/arcshadow.vert.qsb: /opt/qskinny/qsk1/src/nodes/shaders/arcshadow-vulkan.vert
src/.qsb/arcshadow.vert.qsb: /opt/qskinny/config/qsk1/Qt/bin/qsb
src/.qsb/arcshadow.vert.qsb: src/CMakeFiles/qskinny.dir/compiler_depend.ts
@$(CMAKE_COMMAND) -E cmake_echo_color --switch=$(COLOR) --blue --bold --progress-dir=/opt/qskinny/build/qsk1/CMakeFiles --progress-num=$(CMAKE_PROGRESS_2) "Generating .qsb/arcshadow.vert.qsb"
cd /opt/qskinny/build/qsk1/src && /opt/qskinny/config/qsk1/Qt/bin/qsb --glsl 100es,120,150 --hlsl 50 --msl 12 -b -o /opt/qskinny/build/qsk1/src/.qsb/arcshadow.vert.qsb --depfile /opt/qskinny/build/qsk1/src/.qsb/arcshadow.vert.qsb.d /opt/qskinny/qsk1/src/nodes/shaders/arcshadow-vulkan.vert