Hi Mat,
The burden of proof does not fall on you but rather the breeders. If they wanted to they could reveal the steps they took to produce those "Heckels" you have seen.
Schmidt-Focke was able to demonstrate that Hybrids were no longer viable beyond F4 at most. The same thing applies to true green X other discus hybrids.
There is also the issue of mistaken identiy to take into consideration. There are wild discus that appear to be Heckels but are not in fact Heckels.
The plasticity of artificially bred discus has been proven obvious and a Heckel look alikes could be easily be selectively bred from haraldi stock. Phenotypes are not genotypes.(An intriging possibility on it's own merits.)
I do no doubt about what you have seen or heard. I do think there is a lack of proof that stands up to scientific rigor but that certainly is no reflection on you or your contacts. There is a distinct possibility that they got results that appear to pass the test but none that proves their fishes genotype. Phenotypically they could be dead ringers for Heckels yet they may be genotypically haraldi.
It will take years more to sort this out. More breeding experiments with fish of known genotypes carried out over time accompanied with solid documentation.
A very similar controversy is presently on going with regard to the breeding of P. altum angels. Specifically the Linke tank raised Altums. We hear that altums are also regularly bred in the FarEast but the details are just as sketchy. All the same issues and all the same lack of rigorous proofs. So please do not feel anyone, especially me, doubts what you have knowledge of within the limits of the information you have had privy to.
I respect and value you contributions and in no way doubt your sincerity.
I only think that there is more to this than first appears. Discus have a long record of mistaken identification and incomplete disclosure of "proprietary" information. We are all having to deal with this issue.
Larry Waybright