I have fixed the problem and have a solution to the faulty spring. In order fore the shifter to work under stress aka ridning everything must click at the right time and in the right frekvenser. If the spring is as you pictured above an elastic band might help. The damaged spring is supposed to pull the lever mechanism back to the right. Adding a small rubberband will help and take some of the load off the spring. Comment if you need Moore help.
The rubberband is around the small downshifter and the triangular part that is sticking out and causing the problem