2021 Return - download Schwab 1099 data did not populate all data - 2 questions

Just received payment demand from IRS for 2021 missed income (Schwab short-term stock sale income). The income is visible on 2021 1099 now. Why was it missed in the download? Been using TurboTax online for last 4 years.

 

1. Could download process have missed picking up this?

2. Is there any way to see what 1099 data was downloaded? Or indeed can I confirm if I did indeed download the data (I was almost certain I did).

 

Thanks.