I'm not sure that there's a bug, known or otherwise. There's a spot early on when I always think I can go ahead (and I do) and then Taimi doesn't move. Instead, I'm supposed to take a look at something first. I think I've done that story 10 times and I've forgotten 5 times to do that. It's very frustrating right up until I remember to do it. It's a bug ffs ! She just stands still after the fight to protect her at the second pylon. I've walked all around the instance to try and trigger her to move to no avail, I have restarted the quest, the same thing happens. It's 2018, this bug was reported years ago and the expansion is what 3 or more years old now, and it's obviously still not fixed. That's totally unacceptable, I can't get a response from a GM in game, if anet even have them, again that's not acceptable.
