Hi @jclizzy - unfortunately @Vanessa A is 100000% wrong here (not sure what 'Expert' means; probably an AI bot or something). You were correct & you will be taxed in both NY and CA as a result of NY's 'Convenience of the Employer' rule.
If you are working here remotely of your own accord AND your company has not established a bona fide office here in CA; 100% of the income is subject to tax in both states. CA only allows a credit for taxes paid if the income taxed by the other state has a source within the other state under California law (https://www.ftb.ca.gov/forms/2023/2023-540-s-instructions.html).
In laymens terms - if your income was sourced to NY, sure CA would give a credit. BUT, unfortunately, CA considers Wages earned while living/present in this state CA Sourced income. In contrast, NY considers these Wages sourced to NY because you went to CA for your own benefit. CA specifically denies this credit & NJ/CT both are also fighting NY's convenience of the employer rule.
If you filed and got a credit and refund - I would strongly suggest amending your returns. More than likely this will catch up to yo uand you'll hundreds/thousands in income tax, interst, penalties.
