That has nothing to do with reproducible builds - the issue being solved by reproducible builds is that even in exactly the same environment, running the same build script twice can result in differences in the output.
Taken directly from https://reproducible-builds.org/:
"Second, the set of tools used to perform the build and more generally the build environment should either be recorded or pre-defined"
FWIW, I'm a committer on a Linux distro specifically constructed to guarantee build reproducibility (nixos.org), so I'm pretty sure I know what is generally meant by "reproducible builds" in common industry vernacular. Byte-for-byte is important, but that's hardly the whole picture.