Reuters earlier this year - "The development of the 4680 battery has been facing troubles, with the company losing 70% to 80% of the cathodes in test production compared with conventional battery makers, which lose fewer than 2% of their components to manufacturing defects, the report said."

The company L&F referenced in this article were supplying said cathode material.

ref https://www.reuters.com/technology/tesla-plans-four-new-batt...