Applying the patch from Ie6b47f5d192953366911 in VisualEditor did not result in a module change update.
I kept refreshing and purging but nothing happened.
Turns out the way we fetch files in #getModifiedTime is broken for 'skinStyles'.
For some reason, this method duplicates the logic to interpret the 'skinStyles' array structure from #getStyleFiles (instead of using that method), and did so incorrectly causing it to always end up with an empty array.
The bug is quite subtle in that the module is capable of including these files (they're not missing from the css build), it's just that the module cache isn't invalidated if a commit only changed files listed in that part of a module.