The string "6" is a good clue, since your Dumper output shows 6 files. $self->_getGood() returns an array so there's no need to wrap it in @{...}. Try

my $files_to_send = map {"$stage/$_.pdf"} $self->_getGood();
[download]

Cheers,

JohnGG

Update: Doh! My eyes saw $files_to_send, my brain translated to @files_to_send. You could change $self->_getGood() to return the array reference instead, return $self->{_good};