Error updating sessions table

DEBUG MODE

SQL Error : 1062 Duplicate entry 'viewtopic.php?download=20068&f=34&t=1352&_f_=34x&_t_=1352x' for key 'session_page'

UPDATE phpbb_sessions SET session_time = 1784685940, session_start = 1784685940, session_page = 'viewtopic.php?download=20068&f=34&t=1352&_f_=34x&_t_=1352x' WHERE session_id = '5e69de08f01de8437971a6260e08f89b'

Line : 556
File : sessions.php