This maybe just my battle torn lens needing some realignment sense the bottom left corner is the biggest problem.
That would be it, get it repaired - I got even my new lens unaligned and had it replaced. Most CA is easily corrected nowadays, and the corner problem (if you take shots that need this) of the 17-40L diminishes a lot if stopped down - be sure to check with existing sample shots on the net after repair to see if it works properly by then.
So send it to Canon? How long and how much would you guess?