diff --git a/addon/-private/system/relationships/state/has-many.js b/addon/-private/system/relationships/state/has-many.js
index 962a58ffbeb..508552dcde3 100755
--- a/addon/-private/system/relationships/state/has-many.js
+++ b/addon/-private/system/relationships/state/has-many.js
@@ -10,7 +10,6 @@ export default class ManyRelationship extends Relationship {
     super(store, internalModel, inverseKey, relationshipMeta);
     this.belongsToType = relationshipMeta.type;
     this.canonicalState = [];
-    this.isPolymorphic = relationshipMeta.options.polymorphic;
     // The ManyArray for this relationship
     this._manyArray = null;
     // The previous ManyArray for this relationship.  It will be destroyed when
diff --git a/addon/-private/system/relationships/state/relationship.js b/addon/-private/system/relationships/state/relationship.js
index d6c97f5e7b9..2760a9ac822 100644
--- a/addon/-private/system/relationships/state/relationship.js
+++ b/addon/-private/system/relationships/state/relationship.js
@@ -68,7 +68,7 @@ export default class Relationship {
     this.inverseKey = inverseKey;
     this.internalModel = internalModel;
     this.isAsync = typeof async === 'undefined' ? true : async;
-    this.isPolymorphic = typeof polymorphic === 'undefined' ? true : polymorphic;
+    this.isPolymorphic = typeof polymorphic === 'undefined' ? false : polymorphic;
     this.relationshipMeta = relationshipMeta;
     //This probably breaks for polymorphic relationship in complex scenarios, due to
     //multiple possible modelNames