I see some hydraulic leakage under portside rudder, 10 days ago, but also on this same cn 663 years ago.
http://cdn-www.airliners.net/aviatio.../3/2725367.jpg
Took a look at other A321s, it's not very typical for the type. Probably a seal, valve / connection. Luckily both FDR's and the complete wreckage were found so w'll know soon enough.