Fish.

my %rec = ( cuid => "EMPTY" );
scalar <>; # eat first seperator line.
while( <> ) {
  chomp;
  if( /^-+$/ ) {
    print "$rec{username}:$rec{name}:$rec{cuid}\n";
    %rec = ( cuid => "EMPTY" );
  } else {
    my( $k, $v ) = split( /:\s*/, $_, 2 );
    $rec{ lc $k } = $v;
  }
}
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Update: Missed the part about the default.