diff --git a/sytest-blacklist b/sytest-blacklist
index bcc345f6e..e0b2767b1 100644
--- a/sytest-blacklist
+++ b/sytest-blacklist
@@ -49,3 +49,7 @@ Notifications can be viewed with GET /notifications
 
 If remote user leaves room we no longer receive device updates
 Guest users can join guest_access rooms
+
+# You'll be shocked to discover this is flakey too
+
+Inbound /v1/send_join rejects joins from other servers