I don’t owe anything so why did I get half of my state tax return and a full amount on my federal

You would need to contact the state to find out this information.  They likely sent you a letter letting you know why your refund amount changed.  If you did not receive one, you can call the state and ask them why it was reduced.  They do not share this information with TurboTax. 

How do I contact my state Department of Revenue?

MY STATE REFUND WAS LESS THAN I EXPECTED

The state will send you a letter explaining the change.  TurboTax does not get any feedback from your state after your return is accepted, so no one at TT knows why your state refund was less.   Did you owe back taxes, child support, or student loans?  Traffic fines, etc.?

https://ttlc.intuit.com/turbotax-support/en-us/help-article/state-taxes/contact-state-department-revenue/L9qVToi02_US_en_US?uid=m6e06um0

Your state will be sending you a letter in the mail within the next few weeks explaining what they changed on your state tax return to reduce the amount of the refund.