diff --git a/.github/workflows/oci-conformance-action.yml b/.github/workflows/oci-conformance-action.yml
index 021dc6ef..ff0a9e39 100644
--- a/.github/workflows/oci-conformance-action.yml
+++ b/.github/workflows/oci-conformance-action.yml
@@ -38,8 +38,8 @@ jobs:
       with:
         # TODO: change to upstream once the foloowing PR is merged:
         # https://github.com/opencontainers/distribution-spec/pull/436
-        repository: opencontainers/distribution-spec
-        ref: main
+        repository: rchincha/distribution-spec
+        ref: fix-ref
         path: distribution-spec
     - name: build conformance binary from main
       run: |
diff --git a/pkg/api/controller_test.go b/pkg/api/controller_test.go
index 038a241b..d9c0d301 100644
--- a/pkg/api/controller_test.go
+++ b/pkg/api/controller_test.go
@@ -5924,7 +5924,7 @@ func TestArtifactReferences(t *testing.T) {
 				So(err, ShouldBeNil)
 				So(resp.StatusCode(), ShouldEqual, http.StatusOK)
 				So(resp.Header().Get("Content-Type"), ShouldEqual, ispec.MediaTypeImageIndex)
-				So(resp.Header().Get("OCI-Filters-Applied"), ShouldEqual, artifactType)
+				So(resp.Header().Get("OCI-Filters-Applied"), ShouldEqual, "artifactType")
 
 				resp, err = resty.R().SetQueryParams(map[string]string{"artifactType": artifactType +
 					",otherArtType"}).Get(baseURL + fmt.Sprintf("/v2/%s/referrers/%s", repoName,
@@ -5932,7 +5932,7 @@ func TestArtifactReferences(t *testing.T) {
 				So(err, ShouldBeNil)
 				So(resp.StatusCode(), ShouldEqual, http.StatusOK)
 				So(resp.Header().Get("Content-Type"), ShouldEqual, ispec.MediaTypeImageIndex)
-				So(resp.Header().Get("OCI-Filters-Applied"), ShouldEqual, artifactType+",otherArtType")
+				So(resp.Header().Get("OCI-Filters-Applied"), ShouldEqual, "artifactType")
 			})
 		})
 	})
diff --git a/pkg/api/routes.go b/pkg/api/routes.go
index e01e0194..3c809a77 100644
--- a/pkg/api/routes.go
+++ b/pkg/api/routes.go
@@ -624,7 +624,8 @@ func (rh *RouteHandler) GetReferrers(response http.ResponseWriter, request *http
 	}
 
 	if len(artifactTypes) > 0 {
-		response.Header().Set("OCI-Filters-Applied", strings.Join(artifactTypes, ","))
+		// currently, the only filter supported and on this end-point
+		response.Header().Set("OCI-Filters-Applied", "artifactType")
 	}
 
 	zcommon.WriteData(response, http.StatusOK, ispec.MediaTypeImageIndex, out)