diff --git a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/term/TermReadSvcImpl.java b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/term/TermReadSvcImpl.java
index af712a2e197..e8379c4e692 100644
--- a/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/term/TermReadSvcImpl.java
+++ b/hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/term/TermReadSvcImpl.java
@@ -1596,6 +1596,16 @@ public class TermReadSvcImpl implements ITermReadSvc, IHasScheduledJobs {
 		TermConcept code = findCodeForFilterCriteria(theSystem, theFilter);
 
 		if (theFilter.getOp() == ValueSet.FilterOperator.ISA) {
+			ourLog.debug(
+					" * Filtering on specific code and codes with a parent of {}/{}/{}",
+					code.getId(),
+					code.getCode(),
+					code.getDisplay());
+
+			b.must(f.bool()
+					.should(f.match().field("myParentPids").matching("" + code.getId()))
+					.should(f.match().field("myId").matching(code.getId())));
+		} else if (theFilter.getOp() == ValueSet.FilterOperator.DESCENDENTOF) {
 			ourLog.debug(
 					" * Filtering on codes with a parent of {}/{}/{}", code.getId(), code.getCode(), code.getDisplay());
 
diff --git a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/dao/r4/FhirResourceDaoR4TerminologyTest.java b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/dao/r4/FhirResourceDaoR4TerminologyTest.java
index 048e242d700..789e11b60f1 100644
--- a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/dao/r4/FhirResourceDaoR4TerminologyTest.java
+++ b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/dao/r4/FhirResourceDaoR4TerminologyTest.java
@@ -353,7 +353,7 @@ public class FhirResourceDaoR4TerminologyTest extends BaseJpaR4Test {
 			.setSystem(codeSystem.getUrl())
 			.addFilter()
 			.setProperty("concept")
-			.setOp(FilterOperator.ISA)
+			.setOp(FilterOperator.DESCENDENTOF)
 			.setValue("dogs");
 
 		myValueSetDao.create(valueSet, mySrd);
@@ -584,7 +584,7 @@ public class FhirResourceDaoR4TerminologyTest extends BaseJpaR4Test {
 		logAndValidateValueSet(result);
 
 		ArrayList<String> codes = toCodesContains(result.getExpansion().getContains());
-		assertThat(codes, containsInAnyOrder("childAAA", "childAAB"));
+		assertThat(codes, containsInAnyOrder("childAA", "childAAA", "childAAB"));
 
 	}
 
@@ -610,6 +610,34 @@ public class FhirResourceDaoR4TerminologyTest extends BaseJpaR4Test {
 		logAndValidateValueSet(result);
 
 		ArrayList<String> codes = toCodesContains(result.getExpansion().getContains());
+		assertEquals(3, codes.size());
+		assertThat(codes, containsInAnyOrder("childAA", "childAAA", "childAAB"));
+
+	}
+
+	@Test
+	public void testExpandWithDescendentOfInExternalValueSetReindex() {
+		TermReindexingSvcImpl.setForceSaveDeferredAlwaysForUnitTest(true);
+
+		createExternalCsAndLocalVs();
+
+		myResourceReindexingSvc.markAllResourcesForReindexing();
+		myResourceReindexingSvc.forceReindexingPass();
+		myResourceReindexingSvc.forceReindexingPass();
+		myTerminologyDeferredStorageSvc.saveDeferred();
+		myTerminologyDeferredStorageSvc.saveDeferred();
+		myTerminologyDeferredStorageSvc.saveDeferred();
+
+		ValueSet vs = new ValueSet();
+		ConceptSetComponent include = vs.getCompose().addInclude();
+		include.setSystem(TermTestUtil.URL_MY_CODE_SYSTEM);
+		include.addFilter().setOp(FilterOperator.DESCENDENTOF).setValue("childAA").setProperty("concept");
+
+		ValueSet result = myValueSetDao.expand(vs, null); // breakpoint
+		logAndValidateValueSet(result);
+
+		ArrayList<String> codes = toCodesContains(result.getExpansion().getContains());
+		assertEquals(2, codes.size());
 		assertThat(codes, containsInAnyOrder("childAAA", "childAAB"));
 
 	}
@@ -795,7 +823,7 @@ public class FhirResourceDaoR4TerminologyTest extends BaseJpaR4Test {
 		ValueSet vs = new ValueSet();
 		ConceptSetComponent include = vs.getCompose().addInclude();
 		include.setSystem(TermTestUtil.URL_MY_CODE_SYSTEM);
-		include.addFilter().setProperty("concept").setOp(FilterOperator.ISA).setValue("ParentA");
+		include.addFilter().setProperty("concept").setOp(FilterOperator.DESCENDENTOF).setValue("ParentA");
 
 		ValueSet result = myValueSetDao.expand(vs, null);
 		logAndValidateValueSet(result);
@@ -814,7 +842,7 @@ public class FhirResourceDaoR4TerminologyTest extends BaseJpaR4Test {
 		vs = new ValueSet();
 		include = vs.getCompose().addInclude();
 		include.setSystem(TermTestUtil.URL_MY_CODE_SYSTEM);
-		include.addFilter().setProperty("concept").setOp(FilterOperator.ISA).setValue("ParentA");
+		include.addFilter().setProperty("concept").setOp(FilterOperator.DESCENDENTOF).setValue("ParentA");
 		result = myValueSetDao.expand(vs, null);
 		logAndValidateValueSet(result);
 
diff --git a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetNoVerCSNoVerTest.java b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetNoVerCSNoVerTest.java
index 2ab6dd76bf7..a3e9614ff32 100644
--- a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetNoVerCSNoVerTest.java
+++ b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetNoVerCSNoVerTest.java
@@ -202,7 +202,7 @@ public class ResourceProviderR4ValueSetNoVerCSNoVerTest extends BaseResourceProv
 		myLocalVs.setUrl(URL_MY_VALUE_SET);
 		ConceptSetComponent include = myLocalVs.getCompose().addInclude();
 		include.setSystem(codeSystem.getUrl());
-		include.addFilter().setProperty("concept").setOp(FilterOperator.ISA).setValue("ParentA");
+		include.addFilter().setProperty("concept").setOp(FilterOperator.DESCENDENTOF).setValue("ParentA");
 		myLocalValueSetId = myValueSetDao.create(myLocalVs, mySrd).getId().toUnqualifiedVersionless();
 	}
 
@@ -1199,7 +1199,7 @@ public class ResourceProviderR4ValueSetNoVerCSNoVerTest extends BaseResourceProv
 			.setSystem(URL_MY_CODE_SYSTEM)
 			.addFilter()
 			.setProperty("concept")
-			.setOp(FilterOperator.ISA)
+			.setOp(FilterOperator.DESCENDENTOF)
 			.setValue("A");
 		myLocalVs
 			.getCompose()
diff --git a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSNoVerTest.java b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSNoVerTest.java
index 7b56df6dbc8..cb8de80537b 100644
--- a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSNoVerTest.java
+++ b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSNoVerTest.java
@@ -167,7 +167,7 @@ public class ResourceProviderR4ValueSetVerCSNoVerTest extends BaseResourceProvid
 		myLocalVs.setUrl(URL_MY_VALUE_SET);
 		ConceptSetComponent include = myLocalVs.getCompose().addInclude();
 		include.setSystem(codeSystem.getUrl());
-		include.addFilter().setProperty("concept").setOp(FilterOperator.ISA).setValue("ParentA");
+		include.addFilter().setProperty("concept").setOp(FilterOperator.DESCENDENTOF).setValue("ParentA");
 		myLocalValueSetId = myValueSetDao.create(myLocalVs, mySrd).getId().toUnqualifiedVersionless();
 	}
 
diff --git a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSVerTest.java b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSVerTest.java
index cc8d09d8ff7..f10efb5b1f6 100644
--- a/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSVerTest.java
+++ b/hapi-fhir-jpaserver-test-r4/src/test/java/ca/uhn/fhir/jpa/provider/r4/ResourceProviderR4ValueSetVerCSVerTest.java
@@ -196,7 +196,7 @@ public class ResourceProviderR4ValueSetVerCSVerTest extends BaseResourceProvider
 		ConceptSetComponent include = myLocalVs.getCompose().addInclude();
 		include.setSystem(theCodeSystemUrl);
 		include.setVersion(theValueSetVersion);
-		include.addFilter().setProperty("concept").setOp(FilterOperator.ISA).setValue("ParentA");
+		include.addFilter().setProperty("concept").setOp(FilterOperator.DESCENDENTOF).setValue("ParentA");
 		return myLocalVs;
 
 	}