SYSML2_ — Ref Port Displayed with Dashed Lines

In section 8.2.3.12 of the Ports Graphical Notation, ports displayed as shapes have only a solid border, whereas ports on the border of another shape may also have a dashed border, as noted:
"Dotted line port productions (references) are only possible for nested ports."
This implies that a nested port can be displayed on another port with a dashed border. However, based on the BNF, the same nested port cannot be displayed with a dashed border when shown as a regular shape.