diff --git a/callbacks/associations.go b/callbacks/associations.go
index fd3141cf..2107a06a 100644
--- a/callbacks/associations.go
+++ b/callbacks/associations.go
@@ -206,8 +206,8 @@ func SaveAfterAssociations(create bool) func(db *gorm.DB) {
 								}
 							}
 
-							cacheKey := utils.ToStringKey(relPrimaryValues)
-							if len(relPrimaryValues) != len(rel.FieldSchema.PrimaryFields) || !identityMap[cacheKey] {
+							cacheKey := utils.ToStringKey(relPrimaryValues...)
+							if len(relPrimaryValues) == 0 || len(relPrimaryValues) != len(rel.FieldSchema.PrimaryFields) || !identityMap[cacheKey] {
 								identityMap[cacheKey] = true
 								if isPtr {
 									elems = reflect.Append(elems, elem)