I distrib $4k from trad’l IRA, $400 of it to IRS & within 60 days rolled back $4k. shouldn’t 1099R show only $400 distrib?

Enter your 1099R as received into TurboTax.  I would suggest deleting the current 1099R then entering it manually.   After you have logged in and are in your return in TurboTax Online:

• Go to Search at the top of the screen.
• then enter Form 1099-R in the search box. 
• You will see a Jump To function that will take you to the 1099-R input screens. 
• There delete the 1099R in question by clicking on the trash can next to 
• Then add a new 1099R and manually enter your 1099R.

At the financial services screens, click "Change how I enter my form" then "Type it myself"

 

After you enter the 1099R, you will see "Uncommon Situations" Enter "None".  The next screen will ask you if you did a rollover select the 1st option.  From there you can enter the amount you rolled back into the IRA.

 

The pandemic has affected your taxes in many ways. Including reporting in TurboTax the amount of stimulus money you received. Click Here for more information on how the Pandemic affected your 2020  taxes.

When deleting and reentering the Form 1099-R, if TurboTax asks how much was RMD, you must answer None.  Even if the distribution was originally intended to be an RMD, the CARES Act waiving RMDs for 2020 made this not be an RMD.