Board: profile: Last visited = empty

When viewing https://www.phpbb.com/community/memberlist.php?mode=viewprofile&u=252250 the "Last visited" does not have any time although the member should at least show the time when he submitted https://www.phpbb.com/community/viewtopic.php?f=6&t=2232316&p=13617881#p13617881.

To the contrary the "Last visited" part of many other members is filled.

I haven't submitted this to the phpBB tracker since the board here might be optimized/tweaked and thus somehow bypassing session parts for some members. Judging by /includes/session.php his session got never killed, never garbage collected and the login keys got never reset.