Steps to reproduce:
1/ Create a site template
2/ Go to Control Panel, Organization
3/ Choose an organization with no layout in both public and private sections, and choose Layouts
4/ In Public Layouts, choose your site template
6/ In Private Layouts, choose your site template
A message shows that the rrequest has been processed. However, the private pages are still empty.
The same site template is used, and the same Layouts are imported. When trying to create the new one in the private pages, it looks for already existing Layout with the same UUID, but it makes no difference between public and private pages. See in this part of code :
existingLayout is not null, because the very same layout has been created in Public Pages...