1) Create two pages: "target", "linkto"
2) "linkto" page's type is "Link to Page" and "target" page is linked.
3) Switch on the staging
4) Select only the "linkto" page to be published -> Publish
Result: Publishing the page is not possible, exception on the UI: java.lang.NullPointerException, no exceptions in the log
It works when selecting both pages on publishing.
Working in 6.2 as it has a refactored system for dealing with missing references.