I've no idea what I'm doing wrong but unfortunately for me, both a bare $RE... and #$RE... fails for me.

use 5.026;

use Carp;
use Data::Dumper;
use Readonly;
use Regexp::Common qw[ delimited ];
use Regexp::Grammars;
use Try::Tiny;
BEGIN {
    say "Regexp::Common:   $Regexp::Common::VERSION";
    say "Regexp::Grammars: $Regexp::Grammars::VERSION";
    }
try {
    my $grammar = qr{
            <nocontext:>
            <TEST>
            <rule: TEST>           <Quoted_String>
            <token: Quoted_String> $RE{delimited}{-delim=>q{'}}{-esc=>
+q{'}}
            };
    if (q{'some string with containing a '''} =~ $grammar) {
        warn Data::Dumper->new([\%/],[qw(*/)])->Deepcopy(1)->Indent(1)
+->Maxdepth(3)->Sortkeys(1)->Dump(),q{ };
        };
    }
catch { Carp::cluck $_ }; # line 24
try {
    my $grammar = qr{
            <nocontext:>
            <TEST>
            <rule: TEST>           <Quoted_String>
            <token: Quoted_String> #$RE{delimited}{-delim=>q{'}}{-esc=
+>q{'}}
            };
    if (q{'some string with containing a '''} =~ $grammar) {
        warn Data::Dumper->new([\%/],[qw(*/)])->Deepcopy(1)->Indent(1)
+->Maxdepth(3)->Sortkeys(1)->Dump(),q{ };
        };
    }
catch { Carp::cluck $_ }; # line 36
[download]

yields

>perl re.t
Regexp::Common:   2017060201
Regexp::Grammars: 1.057
Not a SCALAR reference at C:/berrybrew/5.32.1_64/perl/site/lib/Regexp/
+Grammars.pm line 106.
 at ..\..\test\re.t line 24.
        main::catch {...} ("Not a SCALAR reference at C:/berrybrew/5.3
+2.1_64/perl/site/li"...) called at C:/berrybrew/5.32.1_64/perl/lib/Tr
+y/Tiny.pm line 123
        Try::Tiny::try(CODE(0xf9c1a0), Try::Tiny::Catch=REF(0x2819630)
+) called at ..\..\test\re.t line 24
Not a SCALAR reference at C:/berrybrew/5.32.1_64/perl/site/lib/Regexp/
+Grammars.pm line 106.
 at ..\..\test\re.t line 36.
        main::catch {...} ("Not a SCALAR reference at C:/berrybrew/5.3
+2.1_64/perl/site/li"...) called at C:/berrybrew/5.32.1_64/perl/lib/Tr
+y/Tiny.pm line 123
        Try::Tiny::try(CODE(0xf9c1a0), Try::Tiny::Catch=REF(0xe581f8))
+ called at ..\..\test\re.t line 36
[download]