This is not the usual stupid .wsf files missing in production build question.
I am using regedit 5.1.3 with an electron-forge application together with webpack and react (no typescript). I get the error

Input Error: Can not find script file "C:UsersalexDesktopprojectdirundefinedvbsregList.wsf"

I have set the custom vbs location like this:

regedit.setExternalVBSLocation(path.join(process.cwd(), "/resources/vbs/"))

I checked 100 times for the path and they are all ok.
Lets take a look at the definitioin of setExternalVBSLocation inside the regedit library

module.exports.setExternalVBSLocation = function(newLocation) {
    if (fs.existsSync(newLocation)) {
        externalVBSFolderLocation = newLocation
        return 'Folder found and set'
    }

    return 'Folder not found'
}

The function should return 'Folder found and set' if the setting went succesfully and 'Folder not found' if it didn’t.
I console logged the calling of the function like so:

console.log(regedit.setExternalVBSLocation(path.join(process.cwd(), "/resources/vbs/")))

An indeed i get Folder found and set!
Now lets take a look at the definition of baseCommand where the actual sauce is happening. This function is called everytime a modification has to be performed to the registry:

function baseCommand(cmd, arch) {
    let scriptPath

    // test undefined, null and empty string
    if (externalVBSFolderLocation && typeof(externalVBSFolderLocation) === 'string') {
        scriptPath = externalVBSFolderLocation
    } else {
        scriptPath = path.join(__dirname, 'vbs')
    }

    return ['//Nologo', path.join(scriptPath, cmd), arch]
}

Focus on the first if condition. According to my situation the condition should be true and it is because i can log to the console before the attribution to scriptPath:

...  
if (externalVBSFolderLocation && typeof(externalVBSFolderLocation) === 'string') {
    console.log(externalVBSFolderLocation) // <-- logging works
    scriptPath = externalVBSFolderLocation
    console.log(scriptPath) // Logs: "C:UsersalexDesktopprojectdirresourcesvbs"
}
...

As you can see everything is normal until i console.log(scriptPath) before the return of baseCommand function:

    ...
    console.log(scriptPath) // Logs some total BULL$HIT: "undefinedvbs"
    return ['//Nologo', path.join(scriptPath, cmd), arch]
}

What in the WORLD is happening. Why the value of scriptPath is different right after it has been attributed?
If I modify the baseCommand function to:

function baseCommand(cmd, arch) {
    return ['//Nologo', path.join(externalVBSFolderLocation, cmd), arch]
}

Everything works like a charm without all those conditions. The problem is that i have to modify the internal code of the package to get it to work…
I want to understand better what is going on with the scriptPath variable. This is a very strange behaviour that I have never seen in programming!