diff --git a/server/src/test/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapperTests.java b/server/src/test/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapperTests.java
index 52e066d69b72f..1130cd8e24f7c 100644
--- a/server/src/test/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapperTests.java
+++ b/server/src/test/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapperTests.java
@@ -93,7 +93,6 @@ protected boolean supportsIgnoreMalformed() {
         return false;
     }
 
-    @Ignore
     @Override
     public void testMapperBuilderSizeMultiField() {}
 
diff --git a/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/GeoShapeWithDocValuesFieldMapperTests.java b/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/GeoShapeWithDocValuesFieldMapperTests.java
index 0ddb38ea500f1..dd5b06ae311b1 100644
--- a/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/GeoShapeWithDocValuesFieldMapperTests.java
+++ b/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/GeoShapeWithDocValuesFieldMapperTests.java
@@ -66,6 +66,12 @@ protected void registerParameters(ParameterChecker checker) throws IOException {
         });
     }
 
+    @Override
+    public void testMapperBuilderSizeMultiField() throws IOException {
+        super.testMapperBuilderSizeMultiField();
+        assertWarnings("Adding multifields to [geo_shape] mappers has no effect and will be forbidden in future");
+    }
+
     protected AbstractShapeGeometryFieldType<?> fieldType(Mapper fieldMapper) {
         AbstractShapeGeometryFieldMapper<?> shapeFieldMapper = (AbstractShapeGeometryFieldMapper<?>) fieldMapper;
         return (AbstractShapeGeometryFieldType<?>) shapeFieldMapper.fieldType();
diff --git a/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/PointFieldMapperTests.java b/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/PointFieldMapperTests.java
index 0e26d9ba0aaf2..3680be6c7bd4f 100644
--- a/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/PointFieldMapperTests.java
+++ b/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/PointFieldMapperTests.java
@@ -63,6 +63,12 @@ protected void registerParameters(ParameterChecker checker) throws IOException {
         });
     }
 
+    @Override
+    public void testMapperBuilderSizeMultiField() throws IOException {
+        super.testMapperBuilderSizeMultiField();
+        assertWarnings("Adding multifields to [point] mappers has no effect and will be forbidden in future");
+    }
+
     public void testAggregationsDocValuesDisabled() throws IOException {
         MapperService mapperService = createMapperService(fieldMapping(b -> {
             minimalMapping(b);
diff --git a/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/ShapeFieldMapperTests.java b/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/ShapeFieldMapperTests.java
index 26d349a7ee5a6..aa5e1507c7786 100644
--- a/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/ShapeFieldMapperTests.java
+++ b/x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/index/mapper/ShapeFieldMapperTests.java
@@ -87,6 +87,12 @@ protected void registerParameters(ParameterChecker checker) throws IOException {
         });
     }
 
+    @Override
+    public void testMapperBuilderSizeMultiField() throws IOException {
+        super.testMapperBuilderSizeMultiField();
+        assertWarnings("Adding multifields to [shape] mappers has no effect and will be forbidden in future");
+    }
+
     protected AbstractShapeGeometryFieldType<?> fieldType(Mapper fieldMapper) {
         AbstractShapeGeometryFieldMapper<?> shapeFieldMapper = (AbstractShapeGeometryFieldMapper<?>) fieldMapper;
         return (AbstractShapeGeometryFieldType<?>) shapeFieldMapper.fieldType();