Don't confuse Residency and Withholding as if that drives taxes. A lot of States also have Source rules, now. Search the web to find what applies, such as:

Google: ca remote worker taxes

https://www.palmspringstaxandtrustlawyers.com/nonresidents-working-remotely-for-california-businesse...

wa remote worker taxes

etc.

Plenty of employers are withholding what doesn't apply. Partly, your taxpayer would be to blame, for not updating the employer, if there truly was a change in residency.

"Staying with family" is not a change of residency, by definition.