Klgan,

ABC/ABN engines, which have been run-in too rich sometimes suffer from reduced hot compression.

Try to feel, with the glow plug and the backplate removed; to cancel out upper and lower compression forces, if you can feel any resistance to turning the engine at TDC (the piston at the very top of the stroke). There should be at least a light "pinch".
If no pinch is evident, your engine is not in good condition.

It can be your break-in technique (too rich), or abrasion from the sand and dust, but abrasive condition damages, usually cannot be felt after less than two hours of running time.

Your warranty must be applicable here and you shouldn't have to pay for piston/cylinder replacement, unless TT can prove you are to blame.

Most engines have better compression when cold, but can still be started, even by flipping, despite the lower hot compression.

If you can start your engine when hot, you can keep using it.

TT has been known to sell the piston/cylinder set just shy of a new engine's price...

Sincerely,