Looking at the AutoIt3Wrapper source code, which is provided in the installation, the following line (line 2326 in my installation) reads:
If $INP_Description = "" Then $INP_Description = FileGetVersion($AutoItBin, "FileDescription")
I believe that to be the source of the Aut2Exe description.
How to force the description to be blank is a bit trickier. The quick and easy hack is to have a script that runs after compilation that removes the description, I usually have reshacker somewhere to hand for tasks like this.
Long term, I will put the issue to the developer, as it seems strange to set a description when the user has explicitly left it blank.