Safari in iOS 8.1.2 (iPhone) does not make an attempt to download the manifest from the server at all when the app is accessed over HTTPS. It works over HTTP.
Could you please provide a URL where the issue could be observed? Does the same site work with Safari 8 on Mac?
I'm a developer and I'm observing the issue with an application that I maintain. It works correctly on iOS 7 and desktop browsers. Will prepare a demo of the issue. Does the same site work with Safari 8 on Mac? Unfortunately I do not have a Mac to test on.
AppCache is now disabled and will be removed in bug 219391.