@Christian Michel
Try and feel along the cable and see if u feel a part that has a thinner diameter or looks like it has been stretched could be damaged wires inside causing problem.
This could happen if you wrap cable up to tidy away wheel etc and they can be sign of problems inside cable.
If you find damaged area you can strip away insulation and inspect the cable and if damaged just re-join wires with connection block or something.
I've repaired g27 pedals this way in the past when they were wrapped to tight hope it may help if you getting a new cable anyway worth a try
Sorry I missed race again , I actually made it home in time but it would have been a bit of a rush and I'd been in traffic for like 4 hours so didn't feel upto it had food instead lol, deffo next race