I've NEVER had a two stroke glow engine of ANY sort from ANY manufacturers, where the head bolts DID NOT loosen after the first few runs.

The engines are usually assembled with the engine cold, so most of the bolts typically loosen after the engine is run.

I run the engine at least TWICE with the cowl off, and while the engine is still warm after it's first runs I tighten down all of the bolts.

It is surprising how loose they can get, especially when seals/gaskets are employed, as the seals compress over time.

Mufflers and muffler fittings also need to be checked.

Once re-tightened the head bolts rarely come loose again.

Muffler fittings are another matter because of the extreme temperature ranges, and in this case a bit of lock-tite helps ( up to a point... ).