Removing an element from map<any type, tinyint/smallint> corrupts commitlog

$ ant build
$ ./bin/cassandra
$ ./bin/cqlsh

CREATE KEYSPACE bugs
    WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'}
    AND durable_writes = true;

CREATE TABLE bugs.bug1 (
    id int,
    m  map<int, tinyint or smallint>, -- key can be any type
    PRIMARY KEY (id)
);

INSERT INTO bugs.bug1 (id, m) VALUES (1, {0: 4, 4: 3});

UPDATE bugs.bug1 SET m[0]=NULL WHERE id=1;
-- and/or UPDATE bugs.bug1 SET m[1]=NULL WHERE id=1;

SELECT * FROM bugs.bug1;

 id | m
----+--------
  1 | {4: 3}

(1 rows)

$ ./bin/nodetool stopdaemon
$ ./bin/cassandra