When using web sources and reaching the point where i have a list of tracks, the data used to tag the file is always from the first tracks on the list, even though another track is selected. I've tried this on several different scripts.
You don't simply select the desired song by clicking on it, you drag it to the top of the list. Or, reorder however the files your tagging are ordered in the main window.
My mistake then. I was always tagging only 1 file and it never occurred to me that i had to reorder, since double clicking a track entry simply wrote the tags to the file. The wrong tags i found out.