I was recently edge jointing some stoc about 5-6' long for glue-up. (I find that this is approaching the capacity of my jointer with a combined bed length of 42". I wasn't paying close enough attenting to my technique and I ended up with a few convex edges. I knew that it was technique and not setup because some of the edges were perfect.
I found that it took several passes on the jointer, carefully watching technique to "fix" the convex edge.
I found it easier (fewer passes) to recover from a concave edge than a convex one.
So, to "fix" a convex edge, I made one pass on the jointer, dropping the stock onto the cutters 6 inches into the cut and lifting it off 6 inches before the end, creating a sort-of concavity. One more regular pass and everything was just right.
Is this an old trick that I just discovered?