An A320 Pilot reported left hand spoilers deployed with the spoiler handle in the down position after take off. The flight Crew requested priority handling and diverted to make a precautionary landing.

Narrative

During preflight; contract Maintenance placarded SEC 3. During startup we had an ELAC 1 fault which was cleared with ECAM. I was PF (Pilot Flying) and after takeoff; the aircraft had a heavy vibration and roll action. We continued the climb and cleaned up the aircraft. We had a FA (Flight Attendant) visually confirm that the left spoilers were deployed with the spoiler handle in the down and disarmed position. We continued to climb and the vibration mostly dissipated but was still evident. After confirmation with Maintenance Control and Dispatch on the Crew Phone; we elected to divert and land in ZZZ instead of continuing to destination ZZZ1. We burned down as much fuel as we could and set up for an approach. When we configured to flaps 2 the serious vibrations started again. We preformed a controllability check at pattern altitude and determined that the vibration was too great at flaps full so we used flaps 3 for landing. As we got closer to the Runway; the vibrations dissipated a bit and we made a normal landing overweight by 10;000 pounds into ZZZ. We had ARFF (Airport Rescue and Fire) inspect the aircraft for damage; which there was none apparent and taxied to a gate and gave the aircraft to maintenance. Our inspection of the aircraft at the gate found the right ground spoiler still extended. We are unsure if that was left over from the flight or just the landing roll. The only indications we received during the flight were the green spoiler arrows on ECAM. No other warnings or messages came up. We were and still are perplexed at how any spoilers could have been extended with the handle stowed. There could have been a secondary malfunction with the SEC 3 issue. It caught us totally by surprise. We followed the placard requirements of the SEC which were very basic. Would like to hear from Maintenance on what the cause was.