That ^@ thingy looks a lot like some binary data with non-printable characters.

As a start you could find out which char it is:

# assuming the string is in $data:
print ord(substr($data, 0, 1)), "\n";
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Then when you know exactly which character it is, you can remove it with a regular expression.

The not-so-safe method would be to remove any leading non-space characters:

$data =~ s/^[^ ]+//;