I have the same issue, the challenge statistics got reset, now all challenges are at 0%. This happened after i played on another computer and didn't syncronize the savegames. I think it had something to do with the different profile of the local savegame and it overwrited the data on the multiplayer server.
How to fix this ?
This is my profile: http://social.bioware.com/n7hq/home/inventory/?name=DrSchmurger&platform=pc
I have 4310 challenge points but most of the challenges are at 0%, which obviously isn't correct.
