Oil analysis suggests stuck rings.

[Dog Ship]

If your really worried about this problem drop your oil pan and see if there are bits of piston ring in the pan. A new oil pan gasket is cheap and it may offer some peace of mind.
Like everone has mentioned it is a broken ring that has caused some scoreing on the cylinder wall. Not a big deal in itself but if you find chucks of ring in your pan you may want to concider honeing the piston holes and installing a new set of rings.
My thoughts on this are' your motor is a piece of safety equipment and should be treated as such. Good luck.

[LakeSuperiorGeezer]

If the head is made of aluminum, cracks are almost guaranteed to exist. Cast iron takes overheating, but not aluminum. By the way, you can weld aluminum heads; however, finding a shop that knows how is a problem and you do not want a crack repair to open up on you when you really need the engine. If you have a crack, exhaust gets into the water jacket and acts like overheating because the exhaust acts like steam sort of. Anyway, get a test kit for exhaust gas in the radiator from an auto parts store and test. It might be that you had a crack in the first place because it took a while for the light to come on. However, you did say you have run the engine for a season so a crack would show coolant in the oil by now.