There are a lot of examples in linguistics where the "correct" pronunciation of a word is not the common pronunciation, and so the common pronunciation becomes the correct one.

I've heard maybe one in every twenty people pronunce it as "jif", and when they do so it's not because it seems like it's the natural pronunciation, it's because they once read it was the correct was to pronounce it and want to hammer that fact home.

So I'm sticking with the hard g version.