Error updating sessions table

DEBUG MODE

SQL Error : 1062 Duplicate entry 'viewtopic.php?download=45611&f=36&t=4039&_f_=36x&_t_=4039x' for key 'session_page'

UPDATE phpbb_sessions SET session_time = 1784685969, session_start = 1784685969, session_page = 'viewtopic.php?download=45611&f=36&t=4039&_f_=36x&_t_=4039x' WHERE session_id = '5e69de08f01de8437971a6260e08f89b'

Line : 556
File : sessions.php