duplicate imports

Somehow I ended up with duplicate 1099-R's in my TT file. It resulted in twice the gross distribution on my form 1040. 

If I import a tax form, such as 1099-R from my brokerage account, and then in a later import I import the same exact form, is TT smart enough to replace the form that came in on the first import or does it simply import it again resulting in duplicate forms? I had always thought that it replaced a duplicate form, but it seems to have added it instead.  Otherwise I can't figure out how I ended up with duplicates.