I think it's because this is getting parsed as:

my $x = '2D6-324';
print(split('-',$x))  ," complete\n";
[download]

so you're printing the split, and the "executing" the text. If you turned on warnings, you'd see "Useless use of a constant in void context". Either add another () enclosing all you want to print, or get rid of the () around split.

-- Dan