[Forminator Pro] single upload fields not working

I have a problem, I have forms that load multiple files, for some of these multiple files and for some single files.

A strange thing happens…
if in the first row of the form I upload a file for example file1.jpg

and i have second row with yes-no condition
at condition yes, another upload opens SINGLE upload
any file I upload in the mail I get another copy of file1.jpg … (the uploaded file in the top line)

For now I fixed it by changing all single upload fields to multi upload field with limitation to one file.
But I would like to know why I have this problem…

thank you!