I fixed a bug that was allowing wasteful file re-downloads from Pixiv and Twitter. I accidentally left a hole in the recent changes to the URL 'neighbour-testing' logic, where it tries to determine if a 'already in db/previously deleted' URL determination is trustworthy, and sites where posts can have multiple files were not able to return 'already in db' or 'previously deleted' until the file itself was redownloaded. I have filled the hole in--thank you for the reports, sorry for the trouble, and let me know if you notice anything else weird going on.