Seems to me that Bahrain and the Gulf area in general are pretty bad as far as exposing aircraft to corrosion.
Besides the obvious salt content in the air from the sea, there is also a problem with SO2 (Sulphur Dioxide), a corrosive bi-product form the petroleum industry's flaring of the poisonous/flamable gases. I would think the A320's are more exposed to this threat, due to the amount of time they spend in the Gulf and on the ground (shorter legs, therefore more ground time and time flying at lower altitudes).