I think what happened was that was tinkering in my project, and at some point was able to manually publish where the name was "Tab_EXP", then when the automation kicked in it added the .tde to the end. So I had two files in Tableau server.
Creates some confusion in the development process, because at the end of the day, the Tableau Dashboard points to "Tab_EXP", not "Tab_EXP.tde". So if you run it manually one time where the file is called "Tab_EXP", build your dashboard off of that file, then add automation where it adds .tde to the name, your dashboard will need to be rebuilt to look at the different "Tab_EXP.tde" file.
Preference is to be consistent either way. I would prefer to not see the .tde from an optics perspective, it's like saving an excel file as name.xlsx.xlsx. Not a huge deal, as long as .tde is added in all cases so you aren't creating multiple files.