Besides looking for documentation I thought you'd perhaps wanted an explanation why Perl's current behaviour is sane and to be expected, and given a way to do achieve what you thought Perl would do for you. Let me set my general reply in context of MAC address parsing:

First things first though: 
  local $_ = join ':', qw/0 0A 0C B B8 F/; # $mac
  my $part = qr/[0-9A-Z]{1,2}/;

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First you used   my @parts = /^($part):($part):($part):($part):($part):($part)$/; which worked. Then you tried to shrink it to 
  my @parts = /
    ^
    (?:
      ($part)
      :
    ){5}
    ($part)
    $
  /x;

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but that didn't work. Now, using "my" technique you just need to add three to four lines to achieve what you want. 
  use re 'eval'; # Needed due to interpolation of $part
  my @parts;
  /
    (?{ local @_parts })

    ^
    (?:
      ($part)
      :
      (?{ local @_parts = (@_parts, $1) })
    ){5}
    ($part)
    $

    (?{ @parts = (@_parts, $2) })
  /x;
The beauty of this technique is that you don't have to know how many times you need/want to match; something that is required if you use the x operator.

If you just want to solve this particular problem, why not simply verify with your second more compact regex and then split it up on /:/?

Update:
Since I got negative response on this reply I reworded the beginning to make it better express what I meant. If it sounded offensive or bad in any way then that wasn't how it was meant and I apologize.

ihb

In reply to Re: Re: Re: Capturing brackets within a repeat group [plus dynamic backreferences] by ihb
in thread Capturing brackets within a repeat group by BrowserUk

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