diff --git a/sytest-blacklist b/sytest-blacklist
index f4c08545..72f62d5e 100644
--- a/sytest-blacklist
+++ b/sytest-blacklist
@@ -21,4 +21,8 @@ Guest users can accept invites to private rooms over federation
 
 # Tests Synapse specific behavior
 /state returns M_NOT_FOUND for an outlier
-/state_ids returns M_NOT_FOUND for an outlier
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+/state_ids returns M_NOT_FOUND for an outlier
+
+# this is a silly restriction as it basically stops servers from communicating, so we relax it
+# see https://github.com/element-hq/synapse/issues/7543
+Server rejects invalid JSON in a version 6 room
\ No newline at end of file