Your boiler is currently cooling itself down after use and hasn't yet finished its normal internal checkout process.

pump / fan overrun

What causes this fault?

This occurs because the boiler needs to dissipate residual heat from the internal heat exchanger after it has finished heating your water or radiators. The pump and fan continue to run briefly to ensure the unit stays within safe temperature limits before it enters standby mode. It is a standard protective measure rather than a breakdown of any internal components.