diff --git a/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/BuildModelTransformer.java b/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/BuildModelTransformer.java
index ac6bcedbf998..2ac066b2283b 100644
--- a/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/BuildModelTransformer.java
+++ b/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/BuildModelTransformer.java
@@ -90,21 +90,10 @@ void handleCiFriendlyVersion(ModelTransformerContext context, Model model, Path
     void handleReactorDependencies(ModelTransformerContext context, Model model, Path pomFile, Model.Builder builder) {
         List<Dependency> newDeps = new ArrayList<>();
         boolean modified = false;
-        String groupId = model.getGroupId();
-        InputLocation groupIdLocation = model.getLocation("groupId");
-        if (groupId == null) {
-            groupId = model.getParent().getGroupId();
-            groupIdLocation = model.getParent().getLocation("groupId");
-        }
         for (Dependency dep : model.getDependencies()) {
             Dependency.Builder depBuilder = null;
-            String depGroupId = dep.getGroupId();
-            if (depGroupId == null) {
-                depGroupId = groupId;
-                depBuilder = Dependency.newBuilder(dep).groupId(groupId).location("groupId", groupIdLocation);
-            }
             if (dep.getVersion() == null) {
-                Model depModel = context.getRawModel(model.getPomFile(), depGroupId, dep.getArtifactId());
+                Model depModel = context.getRawModel(model.getPomFile(), dep.getGroupId(), dep.getArtifactId());
                 if (depModel != null) {
                     String version = depModel.getVersion();
                     InputLocation versionLocation = depModel.getLocation("version");
@@ -112,10 +101,17 @@ void handleReactorDependencies(ModelTransformerContext context, Model model, Pat
                         version = depModel.getParent().getVersion();
                         versionLocation = depModel.getParent().getLocation("version");
                     }
-                    if (depBuilder == null) {
-                        depBuilder = Dependency.newBuilder(dep);
-                    }
+                    depBuilder = Dependency.newBuilder(dep);
                     depBuilder.version(version).location("version", versionLocation);
+                    if (dep.getGroupId() == null) {
+                        String depGroupId = depModel.getGroupId();
+                        InputLocation groupIdLocation = depModel.getLocation("groupId");
+                        if (depGroupId == null && depModel.getParent() != null) {
+                            depGroupId = depModel.getParent().getGroupId();
+                            groupIdLocation = depModel.getParent().getLocation("groupId");
+                        }
+                        depBuilder.groupId(depGroupId).location("groupId", groupIdLocation);
+                    }
                 }
             }
             if (depBuilder != null) {
diff --git a/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/DefaultModelTransformerContextBuilder.java b/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/DefaultModelTransformerContextBuilder.java
index 08a44afcd14d..76d94a6d3130 100644
--- a/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/DefaultModelTransformerContextBuilder.java
+++ b/maven-api-impl/src/main/java/org/apache/maven/internal/impl/model/DefaultModelTransformerContextBuilder.java
@@ -83,7 +83,8 @@ public String getUserProperty(String key) {
             public Model getRawModel(Path from, String gId, String aId) {
                 Model model = findRawModel(from, gId, aId);
                 if (model != null) {
-                    context.modelByGA.put(new GAKey(gId, aId), new Holder(model));
+                    String groupId = DefaultModelBuilder.getGroupId(model);
+                    context.modelByGA.put(new GAKey(groupId, model.getArtifactId()), new Holder(model));
                     context.modelByPath.put(model.getPomFile(), new Holder(model));
                 }
                 return model;
@@ -214,8 +215,18 @@ public ModelTransformerContext build() {
     }
 
     public ModelSource getSource(String groupId, String artifactId) {
-        Set<ModelSource> sources = mappedSources.get(groupId + ":" + artifactId);
-        if (sources == null) {
+        Set<ModelSource> sources;
+        if (groupId != null) {
+            sources = mappedSources.get(groupId + ":" + artifactId);
+            if (sources == null) {
+                return null;
+            }
+        } else if (artifactId != null) {
+            sources = mappedSources.get(artifactId);
+            if (sources == null) {
+                return null;
+            }
+        } else {
             return null;
         }
         return sources.stream()
@@ -231,5 +242,6 @@ public void putSource(String groupId, String artifactId, ModelSource source) {
         mappedSources
                 .computeIfAbsent(groupId + ":" + artifactId, k -> new HashSet<>())
                 .add(source);
+        mappedSources.computeIfAbsent(artifactId, k -> new HashSet<>()).add(source);
     }
 }