Celestial fire melee doesn't activate the exotic perk for Sunbracers consistently, or just not at all when you have the buff from your grenade for gliding. I think the name is heat rises, but it doesn't work when you have it activated.
getting kills with celestial fire also doesn't count for melee kill bounty progress like it should. also doesn't work for impact induction. seems like there's a problem with it registering as a melee ability kill.