We are working on 2020AU. We tried to simplify the following logic by using 'union' or 'flatten'. Both options work in MAT without any errors. However, each option encounters issues.

Single Live Term Newborn Encounter With Newborn to NICU or Discharge to Acute Care or Other Health Care Facility or Expired

• "Sinlge Live Term Newborn Encounter" QualifyingEncounter
  where exists ( QualifyingEncounter.facilityLocations NICU
  where NICU.code in "Neonatal Intensive Care Unit (NICU)"
  )
  or QualifyingEncounter.dischargeDisposition in ( "Patient Expired"
  union "Discharge To Acute Care Facility"
  union "Other Health Care Facility"
  )

Attached contain 3 files. The file named "CMS9_v5_8_Artifacts" works as expected with logic above.

1. The file named "wUNION" can not be  imported into Bonnie with error msg. See error msg in the attachment.
2. The file named "wFlatten" can be imported into Bonnie successfully. However, 3 cases that are testing this logic will not pass Denominator Exclusions as expected. Those cases are DENEXPass DschACF. DENEXPass DschOtherFacility, DENEXPass PtExpired.

We'd like to know the causes so that we can make a decision whether or not we should make this change for this AU.

Thank  you,

Yanyan