Welcome to the forum, Dan (if I may be so bold as to presume!). It’s not a bug that the print preview doesn’t show the exact PDF dimensions when exporting graphics but rather a limitation of the fact that it’s a print preview, i.e. it really is bound to the paper size chosen for the printer. When you export graphics, you’re not using a printer at all, and we’d have to cook up a fictional printer with an appropriate paper size in order to update the print preview, which is easier said than done. I do agree that it can be a bit misleading, though.