Just wanted to follow up on this for who bumps into this kind of issue. The problem was not actually a Sparkle bug.
The problem with the speed-up techniques is they don’t work when loading the page from the Finder directly, and there’s no way to make them compatible.
There are two possible solutions:
- view the site via a web server, so publishing it to a hidden/temporary location on your web server
- export to disk by setting the “offline compatible” option during export setup, this produces a different slower site that works when loaded from the Finder (but you shouldn’t upload this as is to your server because it’s going to be slower)