I have found that occasionally, my Mobile Viewer will hang, when I download a new drawing from my warehouse. I will get the file, but when I try to view it, it will be frozen at a small size. I can’t manipulate it in any way. Even if I try to delete it, or open another file, I stays on that reduced view. Restarting the iPad fixes it.
This also happens if I try to delete and reload a file. Again, I need to restart to make changes apply.