What is the impact of returning to China with a singer's certificate 20 days in advance every six months?

It doesn't matter that your singer license comes back to China 20 days in advance every six months. This is because the validity of the singer visa is half a year, and you can leave the country freely within half a year, so returning to China 20 days in advance will not have any impact on the validity of the visa. As long as the visa is valid, you can continue to use it.

However, it also depends on the specific situation. For example, if there are any other restrictions or regulations on your singer visa, you need to ensure that these regulations are met. In addition, if you plan to leave the country again in a short time after returning to China, you need to confirm whether the visa is still valid.

If you have any uncertainty, it is recommended that you consult the relevant immigration agencies or lawyers to ensure that your behavior conforms to legal provisions and ethical standards.