I was just trying to finish up my return on TurboTax web and noticed this also. I posted the question elsewhere and got a reply from @DianeC958 that is right, put $0 in box 2 for the 1098 you enter that began in 2019. I was just copying what was on the 1098 forms and didn't see the note to enter the principal the amount as of 1/1/2019, which would be $0.
