Sporadic "arr->n_reserved == 0" assertion failures in debug builds

The compact_compressed test sporadically fails in debug builds as follows:

130703 20:10:51 InnoDB: Assertion failure in thread 140684768057120 in file sync/sync0arr.c line 269
InnoDB: Failing assertion: arr->n_reserved == 0
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.1/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
innobackupex: Error:
innobackupex: ibbackup failed at /mnt/workspace/percona-xtrabackup-2.1-param/BUILD_TYPE/debug/Host/centos6-64/xtrabackuptarget/innodb51/innobackupex line

http://jenkins.percona.com/view/XtraBackup/job/percona-xtrabackup-2.1-param/360/BUILD_TYPE=debug,Host=centos6-64,xtrabackuptarget=innodb51/testReport/junit/%28root%29/t_compact_compressed/sh/