Cratering can appear for reasons other than excessively hot loads.

Primers are often what are looked at for high pressure but with the different thicknesses and hard or soft primers it is not the most reliable indicator of pressure. But by the time some pressure signs start showing up pressures are already well above SAAMI Specs. Flattened, cratered, blown or loose primers do indicate pressure, but not totally reliable and sometimes can be just what gets you looking at what else could be the real cause. Shiny spots on the case base, case expansion, sticky bolt lift.... are generally all high pressure signs that you really do want to repeat IMO.

Lacking pressure test equipment which most of us do, a chronograph is one of the best indicators of where we should stop adding more powder to the case. There is a correlation of velocity and pressure and if velocity is high for the round so is pressure.

Excessive oil in the chamber, head space issue are a couple more that can cause primer cratering without excessive pressure.

Another possibility no one has mentioned is the powder could have been below the minimum charge.