This issue was fixed in patch 2.1.9 (https://www.reddit.com/r/elderscrollsonline/comments/3oha91/news_eso_219_patch_notes_readable/)https://www.youtube.com/watch?v=EoIoddfq3Ek&feature=youtu.be
basically the crystal prisms reset themselves every 5 seconds or so. ZoS has ignored my tickets for almost a week
Please note that I've done this quest more than 7 times on other characters. Definitely not my first time
Things I've tried to do:
Abandon the quest and retry
Abandon the quest, leave the dungeon, retry
Abandon the quest, leave the dungeon, log out, retry
Abandon the quest, leave the dungeon, leave Coldharbour, log out, retry
Abandon the quest, leave the dungeon, leave Coldharbour, log out for 8+ hours, retry
Send a support ticket to ZoS (Ticket was discarded because of the IC update, apparently too many people spamming tickets about different things)
Google my a** off, searching most forums, etc. - only found one similar case, and said person said it simply just worked next day. (No source link, sorry guys)
If there's anyone who's ever encountered this, please leave a reply so we can see how wide this problem actually is
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EDIT:
You can bypass this glitch by running back and fourth between the crystals, the progress with the 3rd, 4th, 5th (and so on..) will be saved, it's only the 2nd crystal that resets. It will take some time to complete it, but I guess it's better than waiting 3-4 weeks for Zenimax to fix it.
Clyde Staskunas
@youtube has found a foolproof way to bypass.
Link:
https://www.youtube.com/watch?v=C3WhgOKDohQ