Ghaflah (heedlessness) here describes serious lack of care in transmitting reports. A person may have a capable memory yet fail to exercise necessary scrutiny while listening, recording, protecting a manuscript, or reciting from it.
Illustration: A sentence is added to a transmitter's notebook by another person, and the transmitter later narrates it as heard without checking. This is a schematic illustration, not an attribution to a particular historical narrator.
Heedlessness and excessive error can overlap but are not identical: heedlessness concerns lack of due care, whereas excessive error emphasizes a demonstrably serious pattern of mistakes.