I’ve been doing the PS on a new necro-sylvari, and at the end of Against the Corruption, the story glitched out. On defending Trahearn, I defeated 2 waves (a grand total of 4 baddies) and then it jumped to the cutscene of Trahearn lamenting the ritual failed. Upon leaving the cutscene, everyone was fighting a random risen (Im assuming from the next wave) while Laranthir was yelling about Gretchen falling and needing to kill her.
She never showed up, btw.
This is not my first (or second, or third…) time through, and Ive noticed occasionally some of the triggers (especially for npc dialog) are based on account completion, not character completion, and I dont know if that’s the case here, but I thought I’d mention it.