Hello !
This patch in the issue #423 didn't work if the modules are build in a sub-folder
I added this lines to solve my problem inside the for loop just bellow:
if [[ -f "$build_dir/${built_module_location[$count]}/Module.symvers" ]] ; then
cp -f "$build_dir/${built_module_location[$count]}/Module.symvers" "$tmp_base_dir/module/Module.${built_module_name[$count]}.symvers"
fi