Problem when profiling code snippet with MVM_GC_DEBUG set

gistfile1.txt

dogbert@dogbert-VirtualBox ~ $ MVM_SPESH_DISABLE=1 perl6-gdb-m --profile -e "say 'abcdef' ~~ /<{('a' ... 'z').list}>+/"
================================================================================================
This is Rakudo Perl 6 running in the  debugger, which often allows the user to generate useful back-
traces to debug or report issues in Rakudo, the MoarVM backend or the currently running code.

This Rakudo version is 2019.03.1.408.gf.077.f.57 built on MoarVM version 2019.03.110.g.081823.f,
running on linuxmint (18.3.Sylvia) / linux (42.16.04.1.Ubuntu.SMP.Tue.Oct.10.16.32.20.UTC.2017)

Type `bt full` to generate a backtrace if applicable, type `q` to quit or `help` for help.
------------------------------------------------------------------------------------------------
Reading symbols from /home/dogbert/.rakudobrew/moar-master/install/bin/perl6-m...(no debugging symbols found)...done.
Starting program: /home/dogbert/.rakudobrew/moar-master/install/bin/perl6-m --profile -e say\ \'abcdef\'\ \~\~\ /\<\{\(\'a\'\ ...\ \'z\'\).list\}\>+/
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
MoarVM panic: Adding pointer 0x7ffff6332978 to past fromspace to GC worklist
[Inferior 1 (process 6607) exited with code 01]
(gdb) b MVM_panic
Breakpoint 1 at 0x7ffff74c6934: file src/core/exceptions.c, line 830.
(gdb) r
Starting program: /home/dogbert/.rakudobrew/moar-master/install/bin/perl6-m --profile -e say\ \'abcdef\'\ \~\~\ /\<\{\(\'a\'\ ...\ \'z\'\).list\}\>+/
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, MVM_panic (exitCode=1, messageFormat=0x7ffff7a02a78 "Adding pointer %p to past fromspace to GC worklist") at src/core/exceptions.c:830
830	MVM_NO_RETURN void MVM_panic(MVMint32 exitCode, const char *messageFormat, ...) {
(gdb) bt
#0  MVM_panic (exitCode=1, messageFormat=0x7ffff7a02a78 "Adding pointer %p to past fromspace to GC worklist") at src/core/exceptions.c:830
#1  0x00007ffff76707b1 in mark_gc_entries (tc=0x604d80, ptd=0x3446620, worklist=0x3e25850) at src/profiler/instrument.c:807
#2  0x00007ffff7670b1e in MVM_profile_instrumented_mark_data (tc=0x604d80, worklist=0x3e25850) at src/profiler/instrument.c:830
#3  0x00007ffff7545322 in MVM_gc_root_add_tc_roots_to_worklist (tc=0x604d80, worklist=0x3e25850, snapshot=0x0) at src/gc/roots.c:191
#4  0x00007ffff7548ca7 in MVM_gc_collect (tc=0x604d80, what_to_do=0 '\000', gen=0 '\000') at src/gc/collect.c:121
#5  0x00007ffff753e0fb in run_gc (tc=0x604d80, what_to_do=0 '\000') at src/gc/orchestrate.c:410
#6  0x00007ffff753e56a in MVM_gc_enter_from_allocator (tc=0x604d80) at src/gc/orchestrate.c:527
#7  0x00007ffff753ede6 in MVM_gc_allocate_nursery (tc=0x604d80, size=128) at src/gc/allocation.c:35
#8  0x00007ffff753ebe1 in MVM_gc_allocate (tc=0x604d80, size=128) at src/gc/allocation.h:18
#9  0x00007ffff753ee6f in MVM_gc_allocate_zeroed (tc=0x604d80, size=128) at src/gc/allocation.c:52
#10 0x00007ffff753f212 in MVM_gc_allocate_object (tc=0x604d80, st=0x6712d0) at src/gc/allocation.c:89
#11 0x00007ffff757f85e in allocate (tc=0x604d80, st=0x6712d0) at src/6model/reprs/P6opaque.c:60
#12 0x00007ffff74d5ca2 in MVM_interp_run (tc=0x604d80, initial_invoke=0x7ffff767bde7 <toplevel_initial_invoke>, invoke_data=0x69fa18) at src/core/interp.c:1859
#13 0x00007ffff767bf4c in MVM_vm_run_file (instance=0x604330, filename=0x6042c0 "/home/dogbert/.rakudobrew/moar-master/install/bin/../share/perl6/runtime/perl6.moarvm") at src/moar.c:444
#14 0x00000000004012fd in main ()
(gdb)