Military Income Tax ?

If you are a Texas resident and join the military, do you have to pay Louisiana state tax? The Texas residency is kept the whole time stationed in Louisiana. The tax form was sent to the revenue department in Austin. On the return, it is stated the residency is Texas and the filer is in the military. Also, the majority of that year was spent deployed in a tax free zone. Everything was seemingly filed right. Why would the state claim they're owed tax four years later? Any ideas anyone?