When trying to generate the SSIS package the Output window says Biml expansion completed. but nothing is created. If I copy the generated output from the BIML preview window to a new Biml file, the packages create just fine. What would cause the tool to not pick up the dynamically generated output?
In my experience it is usually locking/waiting of some kind (if you're referencing an external file, server or system), or a delay with the BIML add-in in VS/SSDT. You could try to reinstall BIML to see if that'll help.