From memory, I believe both spoilers should go into over-center (one in each wing), if they is happening then the adjustment would be in the wing that has spoiler hanging open. Adjust the rod that goes between the over-center and the spoiler. I'd want to know why (how) it got so out of adjustment. Could have been an open spoiler hitting the side of the trailer as the wing is returned to the trailer.........look for bent pushrod.
Hope this helps,
JJ