I noticed someone in guild chat comment on this... reflexively checked my mail, saw another task with the same set of rewards... but it didn't come back a third time. I didn't try to replicate it because, lolduh, we're not supposed to be doing that! ... this might've also been after the point Andrew said it'd been fixed.
I imagine this will be like the Glory situation back in March, they'll just fix people individually. Doubt there are too many where its a serious problem.