Interrupting, or getting interrupted, while attempting to use interactive objects in dungeons (e.g. pulling a lever, lighting a rune, or any activity that triggers the “using” bar) that are tied to quest objectives can cause the quest objective to break, preventing quest completion. We are currently working on a fix for this issue. Avoid being struck by combat when attempting to utilize objects that are tied to quest objectives to help mitigate this issue. Thanks for your patience!