So, I'm really curious about this one, this doesn't seem like a legit mechanic, and if it is, I think it should be rethought.

I decided to  use a mutagen on my Symurgh, and it changed it's recessive black colour into a dominant red. I did not know it was supposed to change (or had a chance of changing) dominance?

Here is the pet: http://beastkeeper.com/pet/141851

Is this a bug? If not, then I am really sorry for yet again taking up your time, Angel, I am only trying to help c:

Every gene has 5-6 alleles, not 2, so the dominance may change if the old gene had less genetic power than the second gene in pair, and the new one has more. Please check genetic library for the genetic power of each gene or hover over the gene in pet profile to see what genetic power it has.