NPC Voiceover in Trials missing, or in unintended locations

Instance #1: We queued for Zariel (Master) and throughout the fight, none of Zariel's voiceovers played. The portrait and speech text on the side of the screen did not play either, and there were no entries in the NPC channel of the chat. Most players in the queue experienced this issue, but at least one player did not. Other audio, such as sound effects, worked as normal.

Instance #2: Voiceover from Tiamat has been witnessed (heard, and seen on the side of screen) playing in unintended places like Protector's Enclave and the Summer Festival (pictured below).