Why is the native hiv sequence (which has had a lot of convergence potential since hiv mutates, a lot) different, and why did it convergently evolve instead to

Why is the native hiv sequence (which has had a lot of convergence potential since hiv mutates, a lot) different, and why did it convergently evolve instead to the nucleotide sequence of moderna's artificial furin site (designed for hiv), which to be fair, is subjected to industrial selection, which would be (I would guess, but don't know) weaker than the natural one due to selection sampling limitations?