yes.
In this case  $cgi->param('user_email') returns empty and $cgi->param read the hash-value as a pair. Also it makes  'work_phone' as an undef value eventhough it's valid.
so u should undef the value if it's empty. like

my %data;      = (

'email'=>$cgi->param('user_email') || undef,
'name'=>$cgi->param('user_name') || undef,
'cell_phone'=>$cgi->param('user_cell_phone') || undef,
'home_phone'=>$cgi->param('user_home_phone') || undef,
'work_phone'=>$cgi->param('user_work_phone')|| undef ,
);
[download]

It's shows the exact result for me.
-kulls