There is a known issue with solid state drives produced by Toshiba for Apple. Solid state drives for these particular MacBook Airs (model numbers APPLE SSD TS0128F or APPLE SSD TS0256F) are known to have this issue. It would appear the SMART attribute data for these models of SSD are inaccurate and should not be trusted. As long as the SMART Overall Health Self-Assessment result in the Capabilities tab is reporting a Passed result, the drive can continue to be used.