I received a CP2000 notice from the IRS because I failed to report proceeds from a Charles Schwab Form 1099-B. Is there a reason why Turbo Tax didn't automatically import this form when I used their import feature?

The IRS recently sent me a CP2000 notice for my 2018 tax return. After reviewing the discrepancy, it appears I didn't report the proceeds I had when I sold company's stock contained on Form 1099-B from Charles Schwab. When I worked on my tax return, I used the Turbo Tax import feature to download data from my various financial institutions. It looks like Turbo Tax imported some of the forms from Charles Schwab, but omitted Form 1099-B. While I understand it's my responsibility to double check the data that gets imported into Turbo Tax, I am disappointed that this form was missed (or I didn't get a notification that only a subset of data was imported). I must pay the IRS for the underreporting, which includes an additional negligence penalty and interest. 

Has anyone else ran into a similar problem? Would Turbo Tax ever accept responsibility for covering the negligence penalty and interest?

Thanks!