Your boiler is briefly running its internal pump to circulate water and manage heat after it has been turned off, which is a normal operating state rather than a breakdown.

Pump over run (warm start)

What causes this fault?

This status occurs when the boiler has finished heating your home or water and needs to dissipate the remaining heat from the internal heat exchanger. The pump continues to run for a short period to circulate water and prevent the internal components from getting too hot while the burner is off. It is a protective feature designed to prolong the life of your boiler and is not a sign of a mechanical failure.