diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationExpressions.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationExpressions.java
index e04193d14..2b5e87374 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationExpressions.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/AggregationExpressions.java
@@ -28,7 +28,6 @@ import org.springframework.data.mongodb.core.aggregation.AggregationExpressions.
 import org.springframework.data.mongodb.core.aggregation.AggregationExpressions.Filter.AsBuilder;
 import org.springframework.data.mongodb.core.aggregation.AggregationExpressions.Let.ExpressionVariable;
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
-import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
 import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -3905,31 +3904,19 @@ public interface AggregationExpressions {
 		 */
 		@Override
 		public DBObject toDbObject(final AggregationOperationContext context) {
-
-			return toFilter(new ExposedFieldsAggregationOperationContext(ExposedFields.from(as), context) {
-
-				@Override
-				public FieldReference getReference(Field field) {
-
-					FieldReference ref = null;
-					try {
-						ref = context.getReference(field);
-					} catch (Exception e) {
-						// just ignore that one.
-					}
-					return ref != null ? ref : super.getReference(field);
-				}
-			});
+			return toFilter(ExposedFields.from(as), context);
 		}
 
-		private DBObject toFilter(AggregationOperationContext context) {
+		private DBObject toFilter(ExposedFields exposedFields, AggregationOperationContext context) {
 
 			DBObject filterExpression = new BasicDBObject();
+			InheritingExposedFieldsAggregationOperationContext operationContext = new InheritingExposedFieldsAggregationOperationContext(
+					exposedFields, context);
 
 			filterExpression.putAll(context.getMappedObject(new BasicDBObject("input", getMappedInput(context))));
 			filterExpression.put("as", as.getTarget());
 
-			filterExpression.putAll(context.getMappedObject(new BasicDBObject("cond", getMappedCondition(context))));
+			filterExpression.putAll(context.getMappedObject(new BasicDBObject("cond", getMappedCondition(operationContext))));
 
 			return new BasicDBObject("$filter", filterExpression);
 		}
@@ -6019,27 +6006,14 @@ public interface AggregationExpressions {
 
 		@Override
 		public DBObject toDbObject(final AggregationOperationContext context) {
-
-			return toMap(new ExposedFieldsAggregationOperationContext(
-					ExposedFields.synthetic(Fields.fields(itemVariableName)), context) {
-
-				@Override
-				public FieldReference getReference(Field field) {
-
-					FieldReference ref = null;
-					try {
-						ref = context.getReference(field);
-					} catch (Exception e) {
-						// just ignore that one.
-					}
-					return ref != null ? ref : super.getReference(field);
-				}
-			});
+			return toMap(ExposedFields.synthetic(Fields.fields(itemVariableName)), context);
 		}
 
-		private DBObject toMap(AggregationOperationContext context) {
+		private DBObject toMap(ExposedFields exposedFields, AggregationOperationContext context) {
 
 			BasicDBObject map = new BasicDBObject();
+			InheritingExposedFieldsAggregationOperationContext operationContext = new InheritingExposedFieldsAggregationOperationContext(
+					exposedFields, context);
 
 			BasicDBObject input;
 			if (sourceArray instanceof Field) {
@@ -6050,7 +6024,8 @@ public interface AggregationExpressions {
 
 			map.putAll(context.getMappedObject(input));
 			map.put("as", itemVariableName);
-			map.put("in", functionToApply.toDbObject(new NestedDelegatingExpressionAggregationOperationContext(context)));
+			map.put("in",
+					functionToApply.toDbObject(new NestedDelegatingExpressionAggregationOperationContext(operationContext)));
 
 			return new BasicDBObject("$map", map);
 		}
@@ -6792,22 +6767,7 @@ public interface AggregationExpressions {
 
 		@Override
 		public DBObject toDbObject(final AggregationOperationContext context) {
-
-			return toLet(new ExposedFieldsAggregationOperationContext(
-					ExposedFields.synthetic(Fields.fields(getVariableNames())), context) {
-
-				@Override
-				public FieldReference getReference(Field field) {
-
-					FieldReference ref = null;
-					try {
-						ref = context.getReference(field);
-					} catch (Exception e) {
-						// just ignore that one.
-					}
-					return ref != null ? ref : super.getReference(field);
-				}
-			});
+			return toLet(ExposedFields.synthetic(Fields.fields(getVariableNames())), context);
 		}
 
 		private String[] getVariableNames() {
@@ -6816,20 +6776,23 @@ public interface AggregationExpressions {
 			for (int i = 0; i < this.vars.size(); i++) {
 				varNames[i] = this.vars.get(i).variableName;
 			}
+
 			return varNames;
 		}
 
-		private DBObject toLet(AggregationOperationContext context) {
+		private DBObject toLet(ExposedFields exposedFields, AggregationOperationContext context) {
 
 			DBObject letExpression = new BasicDBObject();
-
 			DBObject mappedVars = new BasicDBObject();
+			InheritingExposedFieldsAggregationOperationContext operationContext = new InheritingExposedFieldsAggregationOperationContext(
+					exposedFields, context);
+
 			for (ExpressionVariable var : this.vars) {
 				mappedVars.putAll(getMappedVariable(var, context));
 			}
 
 			letExpression.put("vars", mappedVars);
-			letExpression.put("in", getMappedIn(context));
+			letExpression.put("in", getMappedIn(operationContext));
 
 			return new BasicDBObject("$let", letExpression);
 		}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/InheritingExposedFieldsAggregationOperationContext.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/InheritingExposedFieldsAggregationOperationContext.java
index c25b56732..2071dc0b6 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/InheritingExposedFieldsAggregationOperationContext.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/InheritingExposedFieldsAggregationOperationContext.java
@@ -13,17 +13,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.data.mongodb.core.aggregation;
 
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
-import org.springframework.util.Assert;
 
 /**
  * {@link ExposedFieldsAggregationOperationContext} that inherits fields from its parent
  * {@link AggregationOperationContext}.
  *
  * @author Mark Paluch
+ * @since 1.9
  */
 class InheritingExposedFieldsAggregationOperationContext extends ExposedFieldsAggregationOperationContext {
 
@@ -40,7 +39,7 @@ class InheritingExposedFieldsAggregationOperationContext extends ExposedFieldsAg
 			AggregationOperationContext previousContext) {
 
 		super(exposedFields, previousContext);
-		Assert.notNull(previousContext, "PreviousContext must not be null!");
+
 		this.previousContext = previousContext;
 	}
 
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java
index 4faddf85d..d89d1a782 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/AggregationTests.java
@@ -143,6 +143,8 @@ public class AggregationTests {
 		mongoTemplate.dropCollection(MeterData.class);
 		mongoTemplate.dropCollection(LineItem.class);
 		mongoTemplate.dropCollection(InventoryItem.class);
+		mongoTemplate.dropCollection(Sales.class);
+		mongoTemplate.dropCollection(Sales2.class);
 	}
 
 	/**