diff --git a/code/internal/+openminds/+abstract/ControlledTerm.m b/code/internal/+openminds/+abstract/ControlledTerm.m
index 5beb166b..fb6bae36 100644
--- a/code/internal/+openminds/+abstract/ControlledTerm.m
+++ b/code/internal/+openminds/+abstract/ControlledTerm.m
@@ -35,7 +35,7 @@
                 propValues.id (1,1) string
             end
 
-            obj.initializeControlledTerm(instanceSpec, propValues)
+            obj = obj.initializeControlledTerm(instanceSpec, propValues);
         end
     end
 end
diff --git a/code/internal/+openminds/+abstract/ControlledTermBase.m b/code/internal/+openminds/+abstract/ControlledTermBase.m
index 14d69693..81fc29c2 100644
--- a/code/internal/+openminds/+abstract/ControlledTermBase.m
+++ b/code/internal/+openminds/+abstract/ControlledTermBase.m
@@ -19,7 +19,13 @@
     end
 
     methods (Access = protected)
-        function initializeControlledTerm(obj, instanceSpec, propValues)
+        function obj = initializeControlledTerm(obj, instanceSpec, propValues)
+        % initializeControlledTerm - Populate one or more terms from a spec
+        %
+        %   The object array is returned because a struct array spec
+        %   produces one term per element. Expanding obj inside this method
+        %   only grows the local copy, so a caller that ignores the return
+        %   value keeps just the first element.
             if isstring(instanceSpec) && isscalar(instanceSpec) && instanceSpec == ""
                 instanceSpec = string.empty;
             end
diff --git a/code/internal/+openminds/+abstract/private/controlledTerms/v2/ControlledTerm.m b/code/internal/+openminds/+abstract/private/controlledTerms/v2/ControlledTerm.m
index fe4ed0c3..c1c19d1f 100644
--- a/code/internal/+openminds/+abstract/private/controlledTerms/v2/ControlledTerm.m
+++ b/code/internal/+openminds/+abstract/private/controlledTerms/v2/ControlledTerm.m
@@ -32,7 +32,7 @@
                 propValues.id (1,1) string
             end
 
-            obj.initializeControlledTerm(instanceSpec, propValues)
+            obj = obj.initializeControlledTerm(instanceSpec, propValues);
         end
     end
 end
diff --git a/code/internal/+openminds/+abstract/private/controlledTerms/v3/ControlledTerm.m b/code/internal/+openminds/+abstract/private/controlledTerms/v3/ControlledTerm.m
index 5beb166b..fb6bae36 100644
--- a/code/internal/+openminds/+abstract/private/controlledTerms/v3/ControlledTerm.m
+++ b/code/internal/+openminds/+abstract/private/controlledTerms/v3/ControlledTerm.m
@@ -35,7 +35,7 @@
                 propValues.id (1,1) string
             end
 
-            obj.initializeControlledTerm(instanceSpec, propValues)
+            obj = obj.initializeControlledTerm(instanceSpec, propValues);
         end
     end
 end
diff --git a/tools/tests/+ommtest/+helper/knownRoundTripGap.m b/tools/tests/+ommtest/+helper/knownRoundTripGap.m
index c5ba8f64..ede3ef4d 100644
--- a/tools/tests/+ommtest/+helper/knownRoundTripGap.m
+++ b/tools/tests/+ommtest/+helper/knownRoundTripGap.m
@@ -23,9 +23,16 @@
 
     reason = "";
 
-    if ismember(typeName, multiValuedControlledInstanceGap())
-        reason = "Multi-valued properties linking to controlled instances " + ...
-            "lose all but the first entry on reload.";
+    if ismember(typeName, ["ParcellationTerminologyVersion", "QuantitativeRelationAssessment"])
+        reason = "Serializing a property that holds an unresolved " + ...
+            "MixedTypeReference fails, because the meta type registry does " + ...
+            "not recognise it as a metadata type.";
+
+    elseif typeName == "ChemicalSubstance"
+        reason = "A controlled instance whose name contains characters that " + ...
+            "are not valid in a MATLAB identifier cannot be looked up from a " + ...
+            "bare reference, so it reloads as an empty term with a new " + ...
+            "blank node identifier.";
 
     elseif typeName == "TermSuggestion"
         reason = "addExistingTerminology is typed as an openMINDS type but " + ...
@@ -35,23 +42,3 @@
             "at all, so fixing it means changing the generator.";
     end
 end
-
-function typeNames = multiValuedControlledInstanceGap()
-% Types holding a multi-valued property that links to controlled instances.
-%
-%   There is no clean structural predicate for these, because many types
-%   with such a property round trip correctly, so they are listed
-%   explicitly. Determined by sweeping every type through save and load.
-
-    typeNames = [ ...
-        "Accessibility", "AtlasAnnotation", "ChemicalSubstance", ...
-        "ContentType", "CustomAnnotation", "DataAnalysis", "DataCopy", ...
-        "DatasetVersion", "Dependency", "File", "FileBundle", ...
-        "FilePathPattern", "GenericComputation", "LocalFile", ...
-        "ModelValidation", "Optimization", "ParcellationTerminologyVersion", ...
-        "QuantitativeRelationAssessment", "Setup", "Simulation", ...
-        "SoftwareVersion", "SubjectGroup", "SubjectGroupState", ...
-        "SubjectState", "TissueSample", "TissueSampleCollection", ...
-        "TissueSampleCollectionState", "TissueSampleState", ...
-        "ValidationTest", "Visualization"];
-end
diff --git a/tools/tests/unitTests/ControlledTermTest.m b/tools/tests/unitTests/ControlledTermTest.m
index dc07f088..167d96f6 100644
--- a/tools/tests/unitTests/ControlledTermTest.m
+++ b/tools/tests/unitTests/ControlledTermTest.m
@@ -30,6 +30,38 @@ function testUserDefinedTermSurvivesDeserialization(testCase)
             testCase.verifyEqual(string(term.id), "_:a-user-defined-term")
         end
 
+        function testStructArrayProducesOneTermPerElement(testCase)
+        % A multi-valued property deserializes to a struct array of
+        % references. Each element must become its own term, or every
+        % entry after the first is lost.
+
+            references = struct('at_id', { ...
+                "https://openminds.om-i.org/instances/laterality/left", ...
+                "https://openminds.om-i.org/instances/laterality/right"});
+
+            terms = openminds.controlledterms.Laterality(references);
+
+            testCase.assertNumElements(terms, 2)
+            testCase.verifyEqual(string(terms(1).id), ...
+                "https://openminds.om-i.org/instances/laterality/left")
+            testCase.verifyEqual(string(terms(2).id), ...
+                "https://openminds.om-i.org/instances/laterality/right")
+        end
+
+        function testMultiValuedControlledPropertyKeepsEveryEntry(testCase)
+        % The same case reached through a property rather than the
+        % constructor, which is how deserialization gets there.
+
+            references = struct('at_id', { ...
+                "https://openminds.om-i.org/instances/laterality/left", ...
+                "https://openminds.om-i.org/instances/laterality/right"});
+
+            annotation = openminds.sands.AtlasAnnotation();
+            annotation.laterality = references;
+
+            testCase.verifyNumElements(annotation.laterality, 2)
+        end
+
         function testReferenceToKnownTermIsLookedUp(testCase)
         % A document carrying only an identifier describes nothing, so the
         % term is populated from the controlled instance library instead.