Steps to reproduce:

1. Edit a page in VE in a namespace with subpages (e.g. User:Foo), that has a subpage (e.g. User:Foo/foo).
2. Open the link dialog.
3. Enter "/f".

Expected: The subpage is shown as suggestion.
Actual: The suggestions come from main namespace.

4. Enter "/foo" completely yourself, insert the link.
5. Review your changes.

Expected: The wikitext inserted is [[/foo]].
Actual: The wikitext is [/foo /foo], which won't even create a link.