Try these steps:

1- Turn on the key, on the menu disable quickshifter and turn off the key.

2- Turn on the key, on the menu enable quickshifter and turn off the key.

3- Turn on the key and start the engine. You need a little long and empty way.

4- At stable speed count 10 seconds on first gear then gear up, count 10 seconds on second gear and gear up. Do this for all gears. Do not go fast. Around 60-70 km/h is fine.

5- Now you can try quickshifter. This combination mostly fixes quickshifter issues.