diff --git a/cypress/e2e/read-receipts/read-receipts.spec.ts b/cypress/e2e/read-receipts/read-receipts.spec.ts
index a36132a408..25334f2a22 100644
--- a/cypress/e2e/read-receipts/read-receipts.spec.ts
+++ b/cypress/e2e/read-receipts/read-receipts.spec.ts
@@ -46,6 +46,9 @@ describe("Read receipts", () => {
             getId: () => eventResponse.event_id,
             threadRootId,
             getTs: () => 1,
+            isRelation: (relType) => {
+                return !relType || relType === "m.thread";
+            },
         } as any as MatrixEvent;
     };