Engraving is fine, cutting suddenly stopped going through — same file as last week

Check in this order, cheapest first:

1. Protective lens. Look at it under a light at an angle. A haze you can barely see costs you 20–30% power. This is the answer 70% of the time.
2. Air assist nozzle blocked with debris — reduced flow means smoke in the beam path.
3. Material. "Same acrylic" from a different batch or supplier can behave differently, and extruded vs cast is a big difference for cutting.
4. Focus — has the material thickness or the bed height changed? A honeycomb bed that's shifted counts.
5. Fan/heat. If the module is running hot because the fan is clogged with dust, output drops.

If a clean lens plus a clean nozzle doesn't restore it, run a power reference test: engrave a fixed line at 50% on scrap and compare to a tile you engraved when the machine was new. That tells you whether it's the machine or the material.