just killed her now, just auto attack when you hit phase two until Calen comes onto the scene and they begin their Kamahameha/galek gun attack thingy, and then go all out with CD's until Calen speaks about sinestra's power waning, keep an eye out for the emote that she channels from the eggs but dont go just yet! wait until you see tendrils of power coming off the eggs to her before you make the attack on the eggs otherwise you'll bug out the fight, happened to me a few times before i caught on.

best of luck!