Interesting reading the AD that has been issued for the elevator solenoid valve o'rings. The part installed
as standard are MS28775-xx. I'm sure they are not suitable for 'Skydrol' or other phosphate ester based hydraulic fluids. In fact I thought they were suitable for fuel and hydrocarbon based hydraulic fluids. They can also be found in use sealing against the elements.
The AD replaces them with NAS1611-xxx seals that are specifically designed for 'Skydrol' type fluids.
Could that have been the fault?
disclaimer: I know nought about things airbus....yet!