thanks for the reply, but i think i got that. from the linked article:

For example, if you changed repo/packages/foo/CHANGELOG.json, when git was getting ready to do the push, it was generating a diff against repo/packages/bar/CHANGELOG.json! This meant we were in many occasions just pushing the entire file again and again, which could be 10s of MBs per file in some cases, and you can imagine in a repo our size, how that would be a problem.

but wouldn’t these erroneous diffs not show up in git diff? it seems that they were pushing (maybe automatically?)without inspecting the diffs first