My own 0.02? This pic is not in itself quite enough.
It appears that there is ''flow'' which could be ascribed to a generous area of chamfer in the primer pocket - so the primer expands to fill that space. There is no view here to see the nature of the area around pin strike ........ if some bad flow there, then probably some over pressure.
I personally expect some flattening ...... in as much as ... at moment of pin strike and then ignition, there is and must be some primer ''set back'' ...... the primer tries to start coming out but is whacked back in at that time.
If the process is too violent then often the metal will start to flow around the firing pin ... that I do not want to see. The flow here tho if due to pocket chamfer, would not in itself strike me as definite over pressure.
My .357 mag case primers usually get pretty flattened but the loads are hot ... but they don't show flow round the pin .... plus, they are within loading limits anyways.