I noticed that a certain symurgh ( namely Niveus) had fertility but was not listed as genetic power. I am wondering,would that be a glitch?

That's because GP has nothing to do with the Fertility gene. 

from FAQ:

What is Genetic Power? How can I get it for my pets?
Genetic Power is a bonus which child will get if the parents were properly trained before conceiving a baby.

The rules of acquiring Genetic Power:

1. If both of the parents have level 50, their child will get +1 Genetic Power.
2. If one of the parents is level 50 and the other is not, the child will get +1 Genetic Power if it has 7 or more dominant genes from the level 50 parent.
3. If both of the parents has similar grade of Genetic Power, the child will get this grade and +1 grade if one or both parents have maximum level (according to the first rule).
4. If parents have a difference of 1 grade of Genetic Power, the child will get the higher grade if it has inherited 7 or more dominant genes from the parent with higher grade. Genetic Power through level can be only acquired but not inherited in this case, thus the levels of parents do not play any role here and do not affect the Genetic Power grade of the child until they are both Lvl 50.
5. If parents has a difference of 2 or more grades of Genetic Power, the child won't get Genetic Power grade for parents' genes, it can get only 1 Grade for parents' levels.
6. Breeding a level 50 pet with no Genetic Power and level < 50 pet with Genetic Power Grade 1 will always result in a baby with Genetic Power Grade 1.