If you run a wing push down on it and you will see that it flexes, causing the wing to flatten out, thus loosing downforce. This is caused by the glue that they stick the skin to the frame has come away from one or the other.
How I fix this is I cut 2 pieces of 4mm thick ally composite panel ( u can use 4mm steel flat bar or something strong that thickness) 100x30mm , push these in either side near the rear mount bolts of wing, between skin and frame. Wear gloves or push it in with something, when it suddenly slips past old glue your fingers hit sharp edge of tin hard and can cut... ask me how I know
