> Maybe the worst part about this is that it can entirely come from a patch being exported by git and then imported straight back in to git.

No one wants to apply diffs in commit messages. But some people use this technique via email:

    Finally fix it

    ---

    Changes in v2:

    - Proper formatting
    - Remove irrelevant typo fix

They’ve used the `---` commit message delimiter in the commit message itself so that everything after it won’t be applied by git-am(1). So that’s intentional loss of round tripping.

I would personally use Git notes instead though.

    Finally fix it

    ---

    Notes:
        Changes in v2: ...