Check the piston to see how you seized.
If it is like 4 corners then it is likely lean jet or vacuum leak.
If it is like just at the exhause port then it is likely too hot a plug (glow is misfiring the cylinder) or timing. Usually the timing shows as high heat as the combustion chamber is retaining too much heat reversion wave from your pipe stuffs it.
Multipoint seize is usually caused by a piston that is mismatched to the size of the cylinder (piston too big).
Cylinder scoring (not much damage to the piston) is from insufficient ring gap.
Would be worth while to take the jug off anyhow so you can ensure there is no galled or smeared aluminium in the ring groove. Carefully remove the smeared material from the upper portion of the groove and the back. Be extremely careful to not put any scratches in the ring groove land where the ring does its job of sealing the combustion chamber.
You can burnish out the smears a little to ensure there is no future contact. If you have a plated bore you can remove aluminium smears with drain openers (carefully - dont get any on anything aluminium though), on cast bores just throw a ball hone through it with lots of kerosene. Plated bores with shadows you can buff it with a butterfly hone made with surgical gauze and some chrome polish.