It is likely to have generic Quando hubs, which are okay for singlespeed use (not the smoothest bearings, but acceptable generally), but have been known to be problematic for use with a fixed gear and no brakes. It seems that in order to make the track hubs cheaply, without having to retool all of their equipment, they ended up re-using the shell of the freewheel hubs, and ended up with a hub that didn't have very many threads for the lockring to attach to. As a result, there were a number of failures where the lockring would break loose of the threads.

I've also heard that this was only a problem with the 'old' hubs, and that they did eventually retool all of their equipment and make a brand new hub with the proper strength for the task.

But I'm a bit foggy on all of this, so do a search and find out!