"Automatically rename [...]" does indeed rename but doesn’t show it (beta)
When added through the Safari Zotero Connector in beta, PDFs are renamed but the name of the PDF isn’t updated in Zotero’s interface (e.g. I still see "Full Text PDF" as the PDF file). Browsing the folder where the file is located confirms that the PDF has indeed been renamed. Closing/reopening Zotero or syncing had no effect.
When you use the manual rename option, there's no translator involved to give the attachment a more descriptive name. You're right that changing the attachment title is a bit inconsistent, but if anything we'd change it to not rename the title in that case, or only rename it if the attachment title already matched the filename exactly. (I actually thought we did the latter, but apparently not.)
Anyway, doesn’t really matter. It’s a small detail and I understand the distinction between attachment title & filename.
Thanks for the answer!
Thanks for the explanation.