From the discussion in
this thread it appears that the `Fix kepub side bearing font cut-off bug
(synced kepubs only)` patch won't work with some synced kepubs.
The kepubs affected are those synced kepubs which don't have an epub2 download option (i.e. ones where the publisher has supplied Kobo with an epub3 instead of an epub2). Using the `Fix kepub side bearing font cut-off bug
(all kepubs)` version of the patch instead will work, but there might be some side effects on the layout of some of those kepubs.