Your boiler is briefly running the internal pump after the heating has switched off to cool down the internal components, which is a normal operation and typically not a fault.

pump overrun

What causes this fault?

This status appears when the boiler's internal computer determines that the heat exchanger is still very hot after a heating or hot water cycle. The pump continues to circulate water briefly to dissipate this residual heat and protect the internal components from overheating. Once the temperature drops to a safe level, the pump will stop and the display will return to normal.