diff --git a/CHANGES.txt b/CHANGES.txt
index c7e4114335..9c0b51b21d 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -111,6 +111,7 @@
  * Restore resumable hints delivery (CASSANDRA-11960)
  * Properly report LWT contention (CASSANDRA-12626)
 Merged from 3.0:
+ * Fix assertion for certain legacy range tombstone pattern (CASSANDRA-12203)
  * Replace empty strings with null values if they cannot be converted (CASSANDRA-12794)
  * Fix deserialization of 2.x DeletedCells (CASSANDRA-12620)
  * Add parent repair session id to anticompaction log message (CASSANDRA-12186)
diff --git a/src/java/org/apache/cassandra/db/UnfilteredDeserializer.java b/src/java/org/apache/cassandra/db/UnfilteredDeserializer.java
index 9e39105015..2c3bc1bc9d 100644
--- a/src/java/org/apache/cassandra/db/UnfilteredDeserializer.java
+++ b/src/java/org/apache/cassandra/db/UnfilteredDeserializer.java
@@ -645,7 +645,7 @@ public abstract class UnfilteredDeserializer
                     // If the new tombstone don't supersedes the currently open tombstone, we don't have anything to return, we
                     // just add the new tombstone (because we know tombstone is not fully shadowed, this imply the new tombstone
                     // simply extend after the first one and we'll deal with it later)
-                    assert metadata.comparator.compare(tombstone.start.bound, first.stop.bound) > 0;
+                    assert metadata.comparator.compare(tombstone.start.bound, first.stop.bound) <= 0;
                     openTombstones.add(tombstone);
                     return null;
                 }