Other templates do it as well, not sure about the standard provided ones. What is strange is I can pull up a recalled print job, delete the images in que and add new ones in place, works fine. If I save it as a layout with the images I can pull up layout and delete the images then add new one and it works. But if I remove the images first, then save as layout then I get the error when adding new images if I use custom... layout... and select that layout.
I have this strange feeling that the Layouts you make are not templates.
If you follow the steps in Learn by Example #9, the steps do not include images anywhere when creating a Layout.
You select the last thumbnail which is labeled Template, and add it to the queue, and size it before or after adding. Then change size to wallet or whatever, and add 4 more templates by clicking the template thumb.
Go to the Full page editor and drag the templates into positions on the page that you like, add floating text, if you wish, like Photo by Alex, position the text, say Done.
Back on the main screen, click File Save, "L" button for Layout, and name it.
Save....
That's a Layout...no pictures involved until I open it from Custom and then add images to make another set of shots with the same sizes and positions that I saved before.
Check HELP, Contents, Learn by example, #9
Fred