.gitattributes override behavior (possible bug, or documentation bug)

According to the gitattributes docs:

"When more than one pattern matches the path, a later line overrides an earlier line. This overriding is done per attribute."

I had a need to do this recently, and while the attributes are git-lfs specific, I think the issue may be generic.

Summary: Trying to apply attributes to file extensions everywhere
except in one directory.

.gitattributes:

    *.[Pp][Nn][Gg] filter=lfs diff=lfs merge=lfs -text
    /.readme-docs/ -filter=lfs -diff=lfs -merge=lfs

Make some data:

    echo "asldkjfa;sldkjf;alsdjf" > ./.readme-docs/test.png
    git add -A

Result:

    "git check-attr -a --cached -- ./readme-docs/test.png" still shows
"filter=lfs diff=lfs merge=lfs" attributes.

Full details: https://github.com/git-lfs/git-lfs/issues/2120#issuecomment-374432354

Is this me misunderstanding something in the documentation? I would expect "./.readme-docs/" to match "./.readme-docs/test.png" and override the earlier "*.[Pp][Nn][Gg]" attributes.

I have found the following overrides to work in lieu of the directory match:

    /.readme-docs/* -filter=lfs -diff=lfs -merge=lfs
    /.readme-docs/**/* -filter=lfs -diff=lfs -merge=lfs

...but I don't see a justification in the documentation for this working and the original directory filter not working.

Thanks for any clarification or help you can provide,

- Dakota