Found this on the official Marvel Heroes forum.
Isn't quest to take down Doom supposed give hero that you don't already have, on 1st playthough?
We know about that issue and we're fixing it. Hang on to the token.
I hope you guys saved your tokens!
Is there anyway to still get the mystery package if I destroyed my duplicated character token? I didnt know it was a bug. :/
We're looking at that.
Seems that those who deleted it will most likely get something still.