Answer: Passiflora pfordtii produces sterile flowers so they never set fruit. At least they're not supposed to set fruit! 'pfordtii' is a hybrid between Passiflora alata and Passiflora caerulea, so perhaps your plant is reverting back. In any event, the fruit is edible. I think it would be interesting to plant the seeds and see what they produce!
Best wishes with your passionflower!
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