We followed the steps above in creating a page and cloning content from an existing page, and it worked as expected. We successfully created Test 1A and Test 2A. Please note that the pages will not appear in the list until you refresh the builder.
We haven’t encountered this issue before, but as a temporary workaround, try creating a new page, clone the content from the pages that aren’t listed, delete the old page, and then rename the replacement page.