Basis in nondeductible traditional IRA contributions is carried forward in TurboTax on TurboTax's IRA Information worksheet, so not needing to file Form 8606 for a particular year has no bearing on TurboTax continuing to carry this information forward. What can happen is either you prepare a tax return without transferring in the previous years TurboTax file or you inadvertently answer No when TurboTax asks if you have such basis, causing TurboTax to silently delete this information that was carried forward.
With regard to splitting the Form 1099-R, that's only necessary if you took a distribution from the traditional IRA and converted part of the distribution and rolled over another part of the distribution. If you didn't convert all of your traditional IRA funds to Roth and still had funds in a traditional IRA at year end, the calculation on Form 8606 cannot allocate all $8,000 of your basis to your otherwise taxable traditional IRA distributions.
