The IRS changed the rules for 1098-T forms starting with tax year 2018, and schools no longer have the option to report amounts billed, meaning that box 2 should either be grayed out or blank. Any amounts that were actually paid in 2018 for qualified tuition and related expenses should be reported in box 1.
In your case, it sounds like the spring 2018 tuition was billed at the end of 2017, and the school reported it in box 2 (amounts billed) of the 2017 1098-T. Because of the rule change and the fact that the spring 2018 expenses were not actually paid until 2018, those expenses appear again on the 2018 1098-T, this time in box 1 (payments received).
I don't use Turbo Tax, so I can't comment about how to make it work the way it should, but the fact that the amount billed for spring 2018 was reported on the 2017 1098-T does not preclude you from taking the AOTC using funds that were actually paid in 2018 for the spring 2018 semester.