I am just learning so even less familiar with lines than color genetics (hopefully one of the really experienced folks will answer)... but my understanding is when Gold/Red based birds are bred with Silver based birds the red/gold bleeds through and is supper hard to breed out even amongst the hens that is why the show bench folks frown on it. In addition I found out there are additional genes which a red/gold based bird might or might not have and that appear not to be sex-linked that effects color and one of those is a non sex linked red/gold gene that can be passed into Silver based birds and it seems to be a gene that is more complicated than straight recessive or dominate.
If they do have the red bleed through it would not surprise me as game fowl are bred first for performance and second for looks, in much the same way egg production birds are bred for performance versus the show bird version of that breed... so a RIR Production line bird will not look the same as a RIR Show line bird, you can tell they are both RIRs but one will look "prettier" than the other, and the less SOP one will probably lay eggs better. The ideal would be a bird that performs the task it is bred for well and looks SOP.
Just some thoughts from a backyard keeper of chickens.
