How it was before:
$ tar tzf qbs-src-1.18.0.tar.gz | head
How it is now:
$ tar tzf qbs-src-1.18.2.tar.gz | head
The presence of additional ._qbs-src-1.18.2 file in the root level breaks Debian build scripts, as it makes them use that level as root directory and not qbs-src-1.18.2/ which should be root.
These are “AppleDouble” files, and apparently you can use COPYFILE_DISABLE=1 environment variable to prevent tar from including them into archive. I do not use macOS so I cannot test that.