You're updating a copy of the hashes.

Fix alternative 1:

sub upd_info
{
    # Create non-reference aliases to arguments.

    our %paramhash;
    local *paramhash = shift;
 
    our @paramarray;
    local *paramarray = shift;
 
    ... keep rest as is ...
}
[download]

Fix alternative 2:

sub upd_info
{
    my ($paramshash, $paramarray) = @_;
 
    while (($key, $val) = each(%$paramhash))             # added $
    {
        $upd_flg = 0;
        foreach $item (sort { $a cmp $b } @$paramarray)  # added $
        {
            if ($item =~ /^$key\s+(\w+)$/)
            {
                $upd_flg = $upd_flg + 1;
                $paramhash->{$key} .= " $1";             # added ->
                last;
            }
        }
        if ($upd_flg == 0)
        {
            $paramhash->{$key} .= " NONE";               # added ->
        }
}
[download]

btw, you're gonna get yourself into trouble sooner or later if you don't tighten the scope of your local variables by using my (my $key; my $val; my $item;, etc) It's best if you use use strict;, which will rightfully complain about these variables.