When entering Form 8606.. Why is nondeductible contribution different amount than what was actually contibuted to traditional IRA?

Hi all, I contributed $7000 to a traditional IRA and converted all of it $7003 to a Roth IRA.  When answering the questions under "Deductions and Credits" it says I can only make $6720 either deductible or non-deductible, which I chose to elect all $6720 nondeductible.

 

The form says $6720 was deductible but $280 was already nondeductible.  Where did Turbotax get this difference of $280 nondeductible vs $6720 deductible option?  No where did I ever say only $280 of the $7000 was nondeductible.  Thank you