All states with income tax believe that income earned in their state is taxable in their state.

CA happens to be rather agressive about it. FWIW, that's why professional athletes end up paying CA taxes. (Interesting question - suppose that your team plays a game in CA but you don't. Do you owe? Does the answer depend on whether you could have played? I heard about a lawsuit arguing about whether practice time, presumably out of state, counted in the apportionment.)

NY is also rather aggressive. I heard of a lawsuit involving an out of state employee who got dinged for visiting corporate headquarters.

I don't recall how the lawsuit (that I know about - there were probably others) over "move out then sell" wrt CA ended. Your tax attorney should.

And no, you shouldn't rely on tax information that you get on HN. Even if I get all the details right, you have no way to know what applies to your situation.