I am currently in Bytom, Poland, working with the countries top athletes. We just finished our first session improving kipping ring muscle-up technique. Breaking the movement down piece by piece and then putting it all back together.
However, having good technique when you're fresh doesn't get you very far in Crossfit. It's not your ability to perform skills that's important, it's your ability to perform them under fatigue over and over again.
Once we had improved the athletes technique, we then did the following workout ... 20 minute assault bike with approx. 25% of the athletes max muscle-ups every 4 minutes (starting on 0:00). The video is towards the end of the workout but nevertheless you can already see the technique starting to break down again. This is why the process has to be progressive. Stage 1 is to maintain solid technique when you're fresh. Stage 2 is to introduce a mono-structural movement with minimal eccentric loading, such as the assault bike at a low-medium pace.
Don't just throw your newly learnt skill into a metcon and question why your technique goes out the window.