Yeah, the current Duolingo version of "gaffel" is totally wrong. The ones on Forvo are perfect.
Which syllable gets stressed? In the Forvo pronunciations, the woman stresses the first syllable, while the male tends to stress more of the second. Is this more of a dialect thing?
Yeah, it's dialectal. The female's pronunciation is more "standard Swedish", I'd say. The male gives the second syllable a bit more oomph (but still not as much as the first syllable).