The flag file_saved of wm is uninitialized when loaded from the blend file. It used to be initialized to 1 after ND_FILEREAD fired.
Before this, there can be other updates to the window title, which render the uninitialized value 0 as an unsaved indicator.

Instead, directly initialize with value 1 so the indicator does not show.

Not sure about a better place to put this initialization, or if there are other code paths where this would not work.