DR bug
I would recommend you contact support and instead of telling them you are suffering from DR, just tell them the amount of xp/karma you got from that Pinion Pass event and list the expected amounts (listed on the wiki). They can investigate and help you troubleshoot.
It could be that DR is broken, but it’s more likely that something else is wrong that is affecting you and/or the specific event(s). I don’t think it’s a generaly issue, since e.g. my guild does dailies together regularly and no one gets hit with DR, even though we tend to spend 60-90 minutes in the same zone.
Good luck.
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