The spoiler I encountered with the same problem had the drain holes plugged which did not let accumulated "sweat" from the inside drain. We sweat alot in Florida ya'll
Good
If you can't tear it off again, try adding your own tiny drain holes w 1/8" drill at the bottom
rear of the vertical element.
Better
Take the wing off to accomplish above.Confirm you hit a void inside the strut vertical.
Reassemble drive at 140mph to test.
mr2tim