diff -u b/core/modules/field/src/Entity/FieldInstanceConfig.php b/core/modules/field/src/Entity/FieldInstanceConfig.php
--- b/core/modules/field/src/Entity/FieldInstanceConfig.php
+++ b/core/modules/field/src/Entity/FieldInstanceConfig.php
@@ -58,10 +58,10 @@
    * The field type.
    *
    * This property is denormalized from the field storage for optimization of
-   * the "entity and render cache hits" critical paths. It is lazy loaded from
-   * the FieldStorageConfig if not specified at __construct() time (see
-   * getType()), and saved in config records so that it is present on the next
-   * load (see toArray()).
+   * the "entity and render cache hits" critical paths. If not present in the
+   * $values passed to entity_create(), it is populated from the
+   * FieldStorageConfig in postCreate(), and saved in config records so that it
+   * is present on the next loads.
    *
    * @var string
    */
@@ -251,7 +251,9 @@
       $field_storage = $values['field_storage'];
       $values['field_name'] = $field_storage->getName();
       $values['entity_type'] = $field_storage->getTargetEntityTypeId();
-      $this->fieldStorage = $field_storage;
+      // The internal property is fieldStorage, not field_storage.
+      unset($values['field_storage']);
+      $values['fieldStorage'] = $field_storage;
     }
     else {
       if (empty($values['field_name'])) {
@@ -287,10 +289,6 @@
    * {@inheritdoc}
    */
   public function getType() {
-    // If not already set, read the field type from the field storage.
-    if (empty($this->field_type)) {
-      $this->field_type = $this->getFieldStorageDefinition()->getType();
-    }
     return $this->field_type;
   }
 
@@ -301,9 +299,12 @@
     // Validate that we have a valid storage for this instance. This throws an
     // exception if the storage is invalid.
     $this->getFieldStorageDefinition();
-    // Also, make sure the denormalized field_type property is populated and
-    // saved in the config records.
-    $this->getType();
+    // If it was not present in the $values passed to entity_create(), (e.g. for
+    // programmatic creation), populate the denormalized field_type property
+    // from the field storage, so that it gets saved in the config record.
+    if (empty($this->field_type)) {
+      $this->field_type = $this->getFieldStorageDefinition()->getType();
+    }
 
     // 'Label' defaults to the field name (mostly useful for field instances
     // created in tests).
only in patch2:
unchanged:
--- a/core/modules/field/tests/src/FieldInstanceConfigEntityUnitTest.php
+++ b/core/modules/field/tests/src/FieldInstanceConfigEntityUnitTest.php
@@ -125,9 +125,13 @@ public function testCalculateDependencies() {
       ->method('getConfigDependencyName')
       ->will($this->returnValue('field.storage.test_entity_type.test_field'));
 
-    $values = array('field_name' => $this->fieldStorage->getName(), 'entity_type' => 'test_entity_type', 'bundle' => 'test_bundle');
-    $entity = new FieldInstanceConfig($values, $this->entityTypeId);
-    $dependencies = $entity->calculateDependencies();
+    $instance = new FieldInstanceConfig(array(
+      'field_name' => $this->fieldStorage->getName(),
+      'entity_type' => 'test_entity_type',
+      'bundle' => 'test_bundle',
+      'field_type' => 'test_field',
+    ), $this->entityTypeId);
+    $dependencies = $instance->calculateDependencies();
     $this->assertContains('field.storage.test_entity_type.test_field', $dependencies['entity']);
     $this->assertContains('test.test_entity_type.id', $dependencies['entity']);
   }
@@ -136,8 +140,12 @@ public function testCalculateDependencies() {
    * @covers ::toArray()
    */
   public function testToArray() {
-    $values = array('field_name' => $this->fieldStorage->getName(), 'entity_type' => 'test_entity_type', 'bundle' => 'test_bundle');
-    $instance = new FieldInstanceConfig($values, $this->entityTypeId);
+    $instance = new FieldInstanceConfig(array(
+      'field_name' => $this->fieldStorage->getName(),
+      'entity_type' => 'test_entity_type',
+      'bundle' => 'test_bundle',
+      'field_type' => 'test_field',
+    ), $this->entityTypeId);
 
     $expected = array(
       'id' => 'test_entity_type.test_bundle.field_test',
@@ -171,4 +179,5 @@ public function testToArray() {
     $export = $instance->toArray();
     $this->assertEquals($expected, $export);
   }
+
 }