Deadlock when using multiple CATCH + rethrow

[ugexe]

The Problem

perl6 -Mnqp -e '                              \
    loop {                                    \
        say ++$;                              \
        CATCH { default { } };                \
        {                                     \
            CATCH { };                        \
            my $ex := nqp::newexception();    \
            try nqp::setmessage($ex, "test"); \
            nqp::rethrow($ex);                \
        }                                     \
    }
'

This program deadlocks. See: https://colabti.org/irclogger/irclogger_log/perl6-dev?date=2019-07-23#l183 -- this is a golf of the deadlock when doing:
perl6 -e 'loop { say ++$; my $r = run("xxx"); }'

but works with MVM_SPESH_DISABLE=1

Expected Behavior

The program should run indefinitely

Actual Behavior

The program deadlocks after some number of iterations

Environment

• Operating system: OSX
• Compiler version (perl6 -v): This is Rakudo version 2019.03.1-683-g20e74837a built on MoarVM version 2019.07-5-gdefe0a959 implementing Perl 6.d.

[voldenet]

Using nqp::throw instead of nqp::rethrow also produces similar bug, but default awaiter users rethrow.

[dogbert17]

This seems to work now with

dogbert@dogbert-VirtualBox:~/repos/rakudo$ perl6 -v
Welcome to 𝐑𝐚𝐤𝐮𝐝𝐨™ v2020.09-88-gc37ffe71b.
Implementing the 𝐑𝐚𝐤𝐮™ programming language v6.d.
Built on MoarVM version 2020.09-15-g4b06df1a6.