Consider D14294, where the final diff has two lines added.
If you look at the first incremental diff ([[https://secure.phabricator.com/D14294?vs=on&id=34503]]), it correctly shows only the single line added.
If you look at the second incremental diff ([[https://secure.phabricator.com/D14294?vs=34503&id=34504]]), it incorrectly shows both lines as added instead of showing just the second line.
Unless I'm misunderstanding, I should be able to get a diff which just shows `frisee`, but all the diffs I seem to be able to generate with that line also include `peanut butter`.