lol everyone who says there's a proper pronunciation needs to just stop.
the english language is entirely moldable, and there are plenty of words out there today pronounced more than one way.
the creator doesn't get to forget to tell everyone how to pronounce his own word and then some years later decide "oh sorry guys turns out it's said exactly the opposite of the way you're saying it"
sure, the intended pronunciation is jiff, but the community written way was and continues to be giff.