I believe it may well be a combination of any and all the things listed above. There is no cam 'sync' to worry about with a Mathews.... but there is cam rotation (set at brace) to check. There are two timing holes on dang near all Mathews bows (the Dren def has them, because thats what bow I shoot myself). They are two small holes, about a tooth pick in diameter each. I use two small allen wrenches, and insert them into those holes. Lay an arrow along the top of the two wrenches, and your arrow should be parrallel to your string. If not, then you need to twist either your string or cable. This really won't cause the issue you are talking about, but it will effect how the bow feels on the draw, and will help you get it back in spec (ie: back to square one).

If on the shot, or just after it, you notice your string is not sitting on the string suppressors, but off to one side, then you have either idler lean (like dryridge was speaking of), or you can actually slide those arms side to side slightly if you back off the allen screws a bit.

Also, and this could just as much be the problem too..... I have seen a Mathews or two come from the factory with what appears to be a limb that shoots off the riser at an odd angle. In both of the cases I've seen of this, Mathews sent a pair of new limbs and a pair of new limb pockets. This has fixed the issue in both cases. If this is the case, you'll probably notice when you draw the bow.... your cable will be rubbing the side of the cam (at the bottom), and you'll feel it slipping into the groves just as you come into the wall. You'll probably have some nasty wear spots on the SIDE (not separation like is typical on single cam bows) of your serving. Mathews is great to deal with, and Bob in their warranty department is a master at diagnosing issues. He has helped me with little nuiances I couldn't figure out many times before.