CPTPP has numerous IP protections, restrictions on state owned enterprises, and a bunch of other encroachments on the members' state sovereignty. China is not going to enter the pact as written. It will either have to be watered down significantly, which defeats the purpose of the agreement as is, or China will not abide by the rules while arguing that they are.

I think China's application is more of a diplomatic/strategic move than an actual intent to join the pact.