This happens only when the folder is in threaded mode. The threaded mode code was missing some code. You can fix it by modifying admin/GMail/Messages/Threads.pm, line ~257, change:
to:
Adrian
Code:
if ($cgi->{msgtrack_nextid} || $cgi->{msgtrack_previd}) {Code:
if (($cgi->{msgtrack_nextid} || $cgi->{msgtrack_previd}) and !$cgi->{stay_put}) {Adrian