SSN errata in ssnx: problem with disjunction between ssn:Property and sosa:FeatureOfInterest

Dear all, I must report an issue I just found with the SSN System
Capability module and the alignment to DUL.

ex. with Survival:

class ssn-system:SurvivalProperty is a sub-class of ssn:Property, and has
for inverseof( ssn-system:hasSurvivalProperty ) only (and at least one)
ssn-system:SurvivalRange, that is a sub-class of *ssn:Property*
inverseof( ssn-system:hasSurvivalProperty ) is a sub-property of
ssn:isPropertyOf
ssn:Property has for ssn:isPropertyOf only *sosa:FeatureOfInterest*

so some instance of ssn-system:SurvivalRange would be both a ssn:Property
and a sosa:FeatureOfInterest, which is forbidden.

For this one, I therefore suggest we accept a feature of interest can also
be a quality, and relax axiom (1) and (2) into (1') and  (2') :

sosa:FeatureOfInterest rdfs:subClassOf [ owl:unionOf ( dul:Event dul:Object
dul:InformationEntity ) ]  (1)
oldssn:FeatureOfInterest owl:equivalentClass sosa:FeatureOfInterest (2)

sosa:FeatureOfInterest rdfs:subClassOf dul:Entity  (1')
oldssn:FeatureOfInterest rdfs:subClassOf sosa:FeatureOfInterest (2')

I created ISSUE #999 on github to report this.

Best,
Maxime