First of all, I am not convinced they are females of N. sp. 'Rio Amaya.' I've yet to see a definitive report about what the females of all the 'new' super-red Nannostomus species/variants look like. Conspiracy theories abound that exporters are shipping females of N. rubrocaudatus or N. marginatus instead to corner the market, or whether the species/variant is color dimorphic at all and exporters can't distinguish the sexes. Their closest relative, N. rubrocaudatus, is dramatically dimorphic in that regard while their other closest relative, N. mortenthaleri, is only slightly so and most folks don't realize it or recognize it.
All that said, in my decades-long experience with Nannostomus-keeping, I've not seen this abnormal patterning to this degree before on any Nannostomus species. I've seen a much milder version that reflected injury but to this degree...I'm at a loss. It's difficult to assess in the photo but the red coloring on the male appears pale---but again, that could be the photo.