my $filename = 'This_filename_has_2  2_spaces.txt';
my $tempstr = "echo \"$filename\" |";
printf "Below is the output of \'$tempstr\'\n";
[download]

It may look like a filename to you, but there's no filename there. All I can see is an "echo" command with a string. From the result printed by echo, the double spaces are turned into a single space. So it seems pretty clear to me that it's the version of `echo` that you have, that causes this.