I did some casual challenge modes with my guild (only some bronzes so far, nothing serious) and my problem is that only one of us was able to see the challenge mode interface (the timer and the progress tracker).
As I see videos on youtube even on most of the gold runs the interface is bugged and isn't visible or shows false details.
I am sure that everyone who did some challenge modes had this problem at least at some of the party members' comupters. Can anyone tell me what addon causes this problems or offer an addon that shows the same details?
I had a similar issue when running through challenge modes. What I ended up doing was starting a challenge mode solo, then logging out and disabling half my addons. If you notice that the timer shows up then you know its in the half that you just disabled. If it doesn't show up then try the other half. Repeat the process on the non-working half until you've narrowed it down.
From what I can tell its usually older addons that haven't been updated in awhile. For me, it was an older addon called SuperDuperMacro that was from before 5.0, but I've heard of several other addons causing problems as well.