Get your taxes done using TurboTax

@rjsVery good point.  I actually had not tried this before (I don't know why, it is such an obvious thing to try).  I was so hoping that this would work and then we could localize the problem to the transfer function of Turbotax. 

I just tried it now and started a new 2020 return from scratch, without transferring anything.  Unfortunately, yes, the exact same thing happens here too.

So here I start with a fresh return, no transfer, enter enough data to get myself to entering a 1099-INT form (just for a direct comparison to my previous posts).  Here is the initial screenshot where I enter the name of the bank:

Now I open a Supporting Document list for the Amount field and enter "Item A" for the description of the first item:

After pressing the Return key, I type in 10.58 for Amount:

And then hit the Return key and see:

I type "Item B" and get:

Now I type 20.00 for the Amount:

And click on "close" and see 305,800.00 as the total for 10.58 + 20.00!!!

Next, I right-click to open the same Supporting Detail list, but before I select the menu item to actually open it, I see the interest income value get multiplied by 100:

And here is when the list is actually opened.  Observe the total in the list, and compare it with the total in the Interest income field (once again increased by 100 times compared to its value in the previous screenshot:

And I just click on "close" to close the list without having changed any of the items in the list:

I think this answers your question.