diff --git a/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/sql/ProtoRowsMergingStateMachine.java b/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/sql/ProtoRowsMergingStateMachine.java
index 68cd7605ac..a4cdae3bec 100644
--- a/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/sql/ProtoRowsMergingStateMachine.java
+++ b/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/sql/ProtoRowsMergingStateMachine.java
@@ -230,6 +230,12 @@ static void validateValueAndType(SqlType<?> type, Value value) {
         checkExpectedKind(value, Value.KindCase.ARRAY_VALUE, type);
         List<Value> fieldValues = value.getArrayValue().getValuesList();
         SqlType.Struct structType = (SqlType.Struct) type;
+        if (fieldValues.size() != structType.getFields().size()) {
+          throw new IllegalStateException(
+              String.format(
+                  "Unexpected malformed struct data. Expected %s fields, received: %s",
+                  structType.getFields().size(), fieldValues.size()));
+        }
         for (int i = 0; i < fieldValues.size(); i++) {
           validateValueAndType(structType.getType(i), fieldValues.get(i));
         }