Companies that do business in California must pay California taxes no matter where they are incorporated.
If an LLC, say software services, incorporated in DE provides some consulting to a firm in California, that counts?
https://www.ftb.ca.gov/businesses/Structures/Limited-Liabili...
And btw that’s the rule in every state. They all want to tax whatever revenue is generated in that state (unless they don’t have a business tax at all, which is somewhat rare)