Why would a freshly opened document think it's modified?
For some documents but not all, right after the document finishes loading, an asterisk will appear in front of the filename, indicating that InDesign thinks there are unsaved changes. Edit->Undo is still grayed out, so there is no action that InDesign thinks I have taken, so what is it doing? There are no errors, no broken links, no missing fonts. If at that point I close the document or ID overall, naturally ID will ask if I want to save changes. It doesn't matter if I say yes or no - the next time I open that document, it will do the same thing.
