CARES Act Disbursement double tax

My 1099-R for a COVID-19 related disbursement shows how I had 10% deducted for Federal taxes and some deducted also for state taxes. Now, when entering the form into TurboTax, I am again having to pay taxes. What the heck is going on? Was the 10% not enough taxes withheld somehow? Now that the 2020 Form 8915-E is finally showing up in the online calculations, it is finally not reflecting that I should also pay the 10% penalty, so what is this extra tax for?