I am attempting to migrate a namespace from one Corteza instance to another. After doing the import, I went to check the roles governing page layout visibility, and discovered that not only did the roles not come across in some cases (not all), but the input box for adding roles is not available on the affected page layouts (see below).
To resolve, this, I end up having to rebuild the affected pages from scratch. Copying the page layout does not work - the role selector field is not visible in the copied pages, either.