diff --git a/sytest-blacklist b/sytest-blacklist
index 65e6c1b16..11841204c 100644
--- a/sytest-blacklist
+++ b/sytest-blacklist
@@ -51,3 +51,6 @@ Remote invited user can see room metadata
 # We don't implement soft-failed events yet, but because the /send response is vague,
 # this test thinks it's all fine...
 Inbound federation accepts a second soft-failed event
+
+# We don't implement lazy membership loading yet.
+The only membership state included in a gapped incremental sync is for senders in the timeline