Do state-owned enterprises need proof of income for job-hopping and employment in private enterprises?

Both state-owned enterprises' job-hopping and private enterprises' employment require proof of income. According to the relevant public information, I know that I have jumped to a new company and asked for proof of the salary and income of the original company. Although this requirement is somewhat wonderful, it does not violate laws and regulations. This requirement is only the company's human resources recruitment management system, which belongs to the company's system regulations. Nothing wrong, no violation of laws and regulations.