I cannot reproduce your problem here. On my machine I ran this code:

use strict;
use warnings;

my $line = 'Width = 32';
if($line =~ m/^Width[\s]*\=[\s]*(\d+)$/) # to match Width
{
    print "Width found: $1\n"
}
elsif ($line =~ m/^Descr[\s]*-[\s]*[\w]+$/) # to match Descr
{
    print 'Descr found'
}
else
{
      printf "Garbage found: \"%s\" \n",$line;
}
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And it prints out Width found: 32

If it doesn't match for you, maybe $line contains some non-printable characters (maybe because the file is stored in UTF-16?)

To find out, you can use something like

use Data::Dumper;
$Data::Dumper::Useqq = 1;
print Dumper $line;
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