Can't breed Aevian ampharos?

[Dicleon]

I got lucky with my mystery egg and got aevian litwick, and i managed to breed it without issues, but i'm breeding for shiny aevian ampharos, and i only get Non aevian mareep; is there no way to get a second one then? And yes my A-Ampharos is a female and i'm using a perfect ditto for breeding.

[Vum]

I think it might be the new 13.4 becuase im pretty sure I saw some people talking about breeding A-ampharos when v13 got released also you could just use debug if your curious about its shiny.