"The lettering looks raised on your chip."

Just the way the shadows fall on the gold HS.

I'd guess that pressure and heat will cause the tiny stress fractures around the lettering.

More pressure and less heat would make this happen. More heat will make the letters too deep and blob.

The correct Temp. and pressure will make a "perfect" hot stamp and every material is different.

These look like they were stamped colder than they should have been, pressing too fast for the plastic/clay to flow.