diff -u b/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php b/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php
--- b/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php
+++ b/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php
@@ -88,9 +88,11 @@
 
     $translatable = FALSE;
     if ($row->getSourceProperty('entity_type') == 'node') {
-      // If this bundle has Content Translation enabled (Drupal 7 Multilingual
-      // Support option "Enabled, with translation") then the row is
-      // translatable.
+      // language_content_type_[bundle] may be
+      //   - 0: no language support
+      //   - 1: language assignment support
+      //   - 2: node translation support
+      //   - 4: entity translation support
       if ($this->variableGet('language_content_type_' . $row->getSourceProperty('bundle'), 0) == 2) {
         $translatable = TRUE;
       }