The IG Publisher added FHIR Path expression checking since the last publication. This checking unearthed a number of issues in the IG. These expressions currently do not work as expected or defined in the descriptions.

Below are the proposed changes with explanations:

Invariant pct-aeob-1

Currently is defined with the expression
extension.where(url='http://hl7.org/fhir/us/davinci-pct/StructureDefinition/serviceDescription').exists() or item.extension.where(url='http://hl7.org/fhir/us/davinci-pct/StructureDefinition/serviceDescription').exists()
However it is being applied to ExplanationOfBenefit.item.extension[serviceDescription]. (in addition to the root ExplanationOfBenefit. ExplanationOfBenefititem.extension does not have the element item as a member. The root ExplanationOfBenefit is the appropriate place to apply the invariant.

• Remove the pct-aeob-1 invariant from ExplanactionOfBenefit.item.extension[serviceDescription]

Invariant pct-aeob-2

Currently is defined with the expression
adjudication.where(category.coding.code='submitted').exists() or item.adjudication.where(category.coding.code='submitted').exists()
 
The issue is that category could have multiple coding elements, which if true causes unexpected results.

• Change pct-aeob-2 to the expression 
  adjudication.where(category.coding.where(code='submitted')).exists() or item.adjudication.where(category.coding.where(code='submitted')).exists()

 
Invariant pct-aeob-3
Currently is defined with the expression
adjudication.where(category.coding.code='submitted').exists() or item.adjudication.where(category.coding.code='submitted').exists()
 
Same kind of issue as pct-aeob-2

• Change pct-aeob-3 to the expression 
  adjudication.where(category.coding.where(code='memberliability')).exists() or item.adjudication.where(category.coding.where(code='memberliability')).exists()
   

Invariant pct-aeob-bundle-2
Currently is defined with the expression
entry.resource.ofType(Organization).exists(type.coding.code='pay')
 
Same kind of issue as pct-aeob-2

• Change pct-aeob-bundle-2 to the expression 
  entry.resource.ofType(Organization).where(type.coding.where(code='pay')).exists()

 
Invariant pct-gfe-bundle-2
Currently is defined with the expression
entry.resource.ofType(Organization).exists(type.coding.code='pay')
 
Same kind of issue as pct-aeob-2

• Change pct-gfe-bundle-2 to the expression 
  entry.resource.ofType(Organization).where(type.coding.where(code='pay')).exists()

Invariant pct-gfe-bundle-1

Currently is defined with the expression
(Bundle.entry.resource.ofType(Claim).extension.where(url='http://hl7.org/fhir/us/davinci-pct/StructureDefinition/gfeSubmitter').valueReference.reference.distinct().count() = 1)
 
However, the proper way in FHIRPath to get a choice element by type is using TypeOf

• Change pct-gfe-bundle-1 to the expression 
  (Bundle.entry.resource.ofType(Claim).extension.where(url='http://hl7.org/fhir/us/davinci-pct/StructureDefinition/gfeSubmitter').value.ofType(Reference).reference.distinct().count() = 1)