SYSML2_ — OccurrenceUsage missing portioningFeature

Clause 8.4.5.2 (Occurrence Usages) says

If an OccurrenceUsage has a non-null portionKind, then it is also required to have a portioningFeature with the same portionKind. The following semantic constraints apply to a PortioningFeature:
...

and the code example at the end of 8.4.5.2 has comments identifying some features as "Portioning", with text below it referring to portioningFeature

However, portioningFeature doesn't appear in Figure 12 (Occurrence Definition and Usage) or anywhere else in the document.