diff --git a/jsonapi.go b/jsonapi.go
index 28240af..7f811ba 100644
--- a/jsonapi.go
+++ b/jsonapi.go
@@ -338,8 +338,8 @@ func (d *document) verifyResourceUniqueness() bool {
 		}
 		topLevelSeen[rid] = true
 
-		relSeen := make(map[string]bool)
 		for _, rel := range ro.Relationships {
+			relSeen := make(map[string]bool)
 			for _, relRo := range rel.getResourceObjectSlice() {
 				relRid := relRo.getIdentifier()
 				if relRo.ID != "" && relSeen[relRid] {
diff --git a/jsonapi_test.go b/jsonapi_test.go
index f9bcd24..f42c5b9 100644
--- a/jsonapi_test.go
+++ b/jsonapi_test.go
@@ -182,6 +182,7 @@ var (
 	articleRelatedCompleteBody                  = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"},"relationships":{"author":{"data":{"id":"1","type":"author"},"meta":{"count":10},"links":{"self":"http://example.com/articles/1/relationships/author","related":"http://example.com/articles/1/author"}},"comments":{"data":[{"id":"1","type":"comments"},{"id":"2","type":"comments"}],"links":{"self":"http://example.com/articles/1/relationships/comments","related":"http://example.com/articles/1/comments"}}}}}`
 	articleRelatedCompleteWithIncludeBody       = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"},"relationships":{"author":{"data":{"id":"1","type":"author"}},"comments":{"data":[{"id":"1","type":"comments"},{"id":"2","type":"comments"}]}}},"included":[{"id":"1","type":"author","attributes":{"name":"A"}},{"id":"1","type":"comments","attributes":{"body":"A"}},{"id":"2","type":"comments","attributes":{"body":"B"}}]}`
 	articleRelatedNonuniqueLinkage              = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"},"relationships":{"author":{"data":{"id":"1","type":"author"}},"comments":{"data":[{"id":"1","type":"comments"},{"id":"1","type":"comments"}]}}}}`
+	articleRelatedDifferentRefToSameObject      = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"},"relationships":{"author":{"data":{"id":"1","type":"author"}},"contact":{"data":{"id":"1","type":"author"}},"comments":{"data":[{"id":"1","type":"comments"}]}}}}`
 	articleRelatedCommentsNestedWithIncludeBody = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"},"relationships":{"comments":{"data":[{"id":"1","type":"comments"}],"links":{"self":"http://example.com/articles/1/relationships/comments","related":"http://example.com/articles/1/comments"}}}},"included":[{"id":"1","type":"comments","attributes":{"body":"A"},"relationships":{"author":{"data":{"id":"1","type":"author"},"links":{"self":"http://example.com/comments/1/relationships/author","related":"http://example.com/comments/1/author"}}}},{"id":"1","type":"author","attributes":{"name":"A"}}]}`
 	articleWithIncludeOnlyBody                  = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"}},"included":[{"id":"1","type":"author","attributes":{"name":"A"}}]}`
 	articleRelatedAuthorLinksOnlyBody           = `{"data":{"id":"1","type":"articles","attributes":{"title":"A"},"relationships":{"author":{"links":{"self":"http://example.com/articles/1/relationships/author","related":"http://example.com/articles/1/author"}}}}}`
@@ -442,6 +443,14 @@ type ArticleRelated struct {
 	Comments []*Comment `jsonapi:"relationship" json:"comments,omitempty"`
 }
 
+type ArticleRelatedWithContact struct {
+	ID       string     `jsonapi:"primary,articles"`
+	Title    string     `jsonapi:"attribute" json:"title"`
+	Contact  *Author    `jsonapi:"relationship" json:"contact,omitempty"`
+	Author   *Author    `jsonapi:"relationship" json:"author,omitempty"`
+	Comments []*Comment `jsonapi:"relationship" json:"comments,omitempty"`
+}
+
 func (a *ArticleRelated) LinkRelation(relation string) *Link {
 	return &Link{
 		Self:    fmt.Sprintf("http://example.com/articles/%s/relationships/%s", a.ID, relation),
diff --git a/unmarshal_test.go b/unmarshal_test.go
index ff93845..524365b 100644
--- a/unmarshal_test.go
+++ b/unmarshal_test.go
@@ -435,7 +435,25 @@ func TestUnmarshal(t *testing.T) {
 			},
 			expect:      ArticleRelated{},
 			expectError: ErrNonuniqueResource,
-		}, {
+		},
+		{
+			description: "ArticleRelatedWithContact (nonunique linkage)",
+			given:       articleRelatedDifferentRefToSameObject,
+			do: func(body []byte) (any, error) {
+				var a ArticleRelatedWithContact
+				err := Unmarshal(body, &a)
+				return &a, err
+			},
+			expect: &ArticleRelatedWithContact{
+				ID:       "1",
+				Title:    "A",
+				Author:   &Author{ID: "1"},
+				Comments: []*Comment{{ID: "1"}},
+				Contact:  &Author{ID: "1"},
+			},
+			expectError: nil,
+		},
+		{
 			description: "links member only",
 			given:       `{"links":null}`,
 			do: func(body []byte) (any, error) {