Lean seizure is the most common problem with chain saws. In these photos of replacement cylinder kits that lasted less than a month, you can see the excessive scoring on the exhaust side. The rings are practically melted into the piston. Running lean causes the saw to overheat which melts the piston. Several things can cause this problem. It could be a bad carburetor, bad fuel mix, crank seals could be leaking, intake boot leak, cylinder gasket leak, carb needs to be adjusted, etc.
Things that often are blamed but are NOT the cause of this often include, port chamfers, bad plating, machining errors, faulty rings, failed wrist pin clips, or cheap materials. If a poorly shaped exhaust port was to blame then there would be a rounded or chipped edge on the rings.
Whatever killed the original cylinder was not that the cylinder and piston went bad. So replacing the cylinder and piston kit did not fix the issue. Imagine your house has a leak in the plumbing and water is getting into one of the rooms, so you shop vac all the water and put damp rid in the room thinking that will fix the problem, but you did nothing to stop the leak. Then you blame your shop vac for not getting the problem fixed. Sounds silly doesn’t it? But that is what many people do when they keep putting new cylinders and pistons on their saws, they blow up again and they call the parts company and demand they send them another cylinder and piston kit for free.