Your boiler is briefly keeping the pump running to dissipate excess heat after heating your hot water, which is a normal operational status rather than a breakdown.

Pump over run (hot water operation)

What causes this fault?

This status occurs when the boiler has finished heating your hot water cylinder and needs to clear remaining heat from its internal heat exchanger. It keeps the pump running for a short period to move that residual heat away into your system, preventing the internal components from overheating. This is a standard safety feature and simply means the boiler is 'cooling down' naturally after a period of hard work.