A rules question: problems are tracks, right? are problems rolled at any point? or why do they have a die size instead of just a number of boxes for the track?
Problems are tracks, correct! You can roll for a problem whenever it makes sense to: if you spent a downtime activity to work on it, or did something during a job that would solve that problem. The use of "D6" and so forth to describe the size of them is just a quirk.