The capturing parentheses in a regex expresson like  qr/(?:(simple).*?)+/ always capture to the same capture group no matter how many times they may be 'repeated' by a quantifier. Which capture group (by number) is determined by the position of the capturing parentheses in the final regex. After interpolation, the statement
    $string =~ /$re$re$re/g;
looks like
    $string =~ /(?:(simple).*?)+(?:(simple).*?)+(?:(simple).*?)+/g;
which clearly contains three sets of capturing parentheses, capturing to  $1 $2 $3 respectively.

Perhaps a way to do what you want is: 

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $re = qr/(?:(simple).*?)+/;
 ;;
 my $string = 'This is a simple string, just a simple simple thing.';
 my @captures = $string =~ /$re/g;
 dd \@captures;
"
["simple", "simple", "simple"]

[download]

Update: This particular example can be expressed even more simply as: 

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $re = qr/simple/;
 ;;
 my $string = 'This is a simple string, just a simple simple thing.';
 my @captures = $string =~ /$re/g;
 dd \@captures;
"
["simple", "simple", "simple"]

[download]

In reply to Re: Matching a regular expression group multiple times by AnomalousMonk
in thread Matching a regular expression group multiple times by Anonymous Monk

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