SYSML2 — timeslice/snapshot featuring types required to specialize or be same as types

Clause 8.3.9.5 (OccurrenceUsage), Constraints, says

checkOccurrenceUsageTypeFeaturing
If the portionKind of an OccurrenceUsage is not empty, then, for each occurrenceDefinition of the OccurrenceUsage, there must be a featuringType of the OccurrenceUsage which either is the occurrenceDefinition or directly or indirectly specializes it.

portionKind <> null implies
  occurrenceDefinition->forAll(occ |
    featuringType->exists(specializes(occ)))

For example, adapted from 7.13.5 (Successions as Usages):

occurrence def Flight {
  timeslice preflight : Preflight [1];
  then timeslice inflight : Inflight [1];
  then timeslice postflight : Postflight[1];

checkOccurrenceUsageTypeFeaturing requires Flight to specialize each of Pre/In/Postflight, even though these would typically be disjoint with Flight, leading to:

• all features defined in Pre/In/Postflight "inheriting" to Flight, eg, PreFlight::refuel, would inherit to Flight, with a separate value potentially unconstrained in time from the one happening in preflight.

• valid traces where all the pre/in/postflight values are instances of Flight, which are all required to have pre/in/postflight timeslices.

which probably aren't intended in this exampe.