A little late, sorry, but I don't like the answers here.
It just happened once with the one character. after turning into two forms the male form was killed so returning it back to its genderless state is impossible. though it was a natural occurrence used as a way for the character to make sure that at least a part of it survived an encounter it wasn't sure it could survive. that way time could continue flowing as it is the god of time
Losing that ability could be called gender bender, since it would leave them as a girl, no longer the gender they once were. However, it's mostly irrelevant, because-
I see. sadly, it isn't a protagonist so I don't think I can use that tag. It's more like a watcher who aids the protagonist as well as hinders them.
It isn't the protagonist, and I assume it isn't a major plot point. The tag isn't there just to be tacked on for a brief mention and some extra views, it shows what the story is about. It
IS gender bender, but your story doesn't need the gender bender tag since it isn't what the story is about.