The product is written as a patented product and has a patent number. Does the formula of this product have to be in accordance with the formula in the patent application?

There is nothing illegal or legal about this;

If he applies for a patent, he has the right to use the patent. Within the legal scope, it is his business how he wants to use the patent.

The product packaging usually shows some conventional ingredients. Besides, his patent has been made public.

So, he is not afraid of others plagiarizing it. After all, once Plagiarism also results in patent infringement.