She should be filing the Georgia state income tax return as Married Filing Separately since her spouse is a nonresident and does not have any Georgia sourced income. She still should be filing the federal tax return as Married Filing Jointly.
The reason the for the high amount of taxes was because she is filing Married Filing Jointly on the Georgia tax return and her spouse's income is being included on the state return.
See this TurboTax support FAQ for filing separately on a state return and jointly on a federal return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/small-business-processes/prepare-joint-f...
