Not a workaround. It’s quite direct. 
That additional script is causing the problems. Why is it not known what it is doing? Who benefits of it? What do you miss when you don’t use it?
I rather have the import window so I know what’s going on.
George
Or if you’re working on a folder, set that folder to be watched with LR’s auto-import. That’s even faster. I’ll look at the Lightroom LUA API if we can change the watched folder in a script. Because that would be the best solution for a simple script: just add that line to the export to PL5 lua script, so that the watched folder becomes the one the original file is in. Then simply select “export to disk” when done. LR will then automatically import the new file, without even quitting the develop or library view.