The aileron is at times sat happily with its 5 degree droop with flap extended at its neutral position with the spoilers extended... it can't be for roll control.
I'm going with TyroPicard's explanation. I have seen it twice for real on the A320... once after takeoff, only noticed once the *bing* Ecam caution appeared to warn that the spoilers are extended against power and once leading to a high speed RTO during base training (Ecam threw up T/O config master warning). Airbus SOP changed to disarm ground spoilers now after flap retraction for this very reason.
Guessing here: With the T/O explanation I would think they received the ECAM caution fairly early on, but elected to have a look at it once things settled down a bit on departure.. which is a good thing with an amber caution... then once you have the aircraft on a safe trajectory have a look and diagnose.