Server crashes in check_vcol_forward_refs upon INSERT DELAYED into table with long blob key

CREATE  TABLE t1 (a BLOB, UNIQUE(a)) ENGINE=MyISAM;

INSERT DELAYED t1 () VALUES ();

# Cleanup

DROP TABLE t1;

#3  <signal handler called>

#4  0x0000564907943457 in check_vcol_forward_refs (field=0x7fe3b4015638, vcol=0x7fe3b4015718, check_constraint=false) at /data/src/10.4/sql/table.cc:3445

#5  0x000056490793b963 in parse_vcol_defs (thd=0x7fe3b4000b00, mem_root=0x7fe3b4006470, table=0x7fe3b40146e8, error_reported=0x7fe3c5a2303b) at /data/src/10.4/sql/table.cc:1260

#6  0x00005649077de686 in Delayed_insert::get_local_table (this=0x7fe3b4182250, client_thd=0x7fe3b4000b00) at /data/src/10.4/sql/sql_insert.cc:2627

#7  0x00005649077dddc4 in delayed_get_table (thd=0x7fe3b4000b00, grl_protection_request=0x7fe3c5a23170, table_list=0x7fe3b40131f0) at /data/src/10.4/sql/sql_insert.cc:2457

#8  0x00005649077d8fe0 in open_and_lock_for_insert_delayed (thd=0x7fe3b4000b00, table_list=0x7fe3b40131f0) at /data/src/10.4/sql/sql_insert.cc:573

#9  0x00005649077d95c9 in mysql_insert (thd=0x7fe3b4000b00, table_list=0x7fe3b40131f0, fields=..., values_list=..., update_fields=..., update_values=..., duplic=DUP_ERROR, ignore=false) at /data/src/10.4/sql/sql_insert.cc:759

#10 0x0000564907824e2a in mysql_execute_command (thd=0x7fe3b4000b00) at /data/src/10.4/sql/sql_parse.cc:4512

#11 0x0000564907830cdb in mysql_parse (thd=0x7fe3b4000b00, rawbuf=0x7fe3b4013108 "INSERT DELAYED t1 () VALUES ()", length=30, parser_state=0x7fe3c5a24180, is_com_multi=false, is_next_command=false) at /data/src/10.4/sql/sql_parse.cc:7892

#12 0x000056490781cf85 in dispatch_command (command=COM_QUERY, thd=0x7fe3b4000b00, packet=0x7fe3b4008311 "INSERT DELAYED t1 () VALUES ()", packet_length=30, is_com_multi=false, is_next_command=false) at /data/src/10.4/sql/sql_parse.cc:1827

#13 0x000056490781b743 in do_command (thd=0x7fe3b4000b00) at /data/src/10.4/sql/sql_parse.cc:1360

#14 0x0000564907994993 in do_handle_one_connection (connect=0x56490ad3f010) at /data/src/10.4/sql/sql_connect.cc:1403

#15 0x00005649079946f7 in handle_one_connection (arg=0x56490ad3f010) at /data/src/10.4/sql/sql_connect.cc:1306

#16 0x00005649082bfe49 in pfs_spawn_thread (arg=0x56490ad743a0) at /data/src/10.4/storage/perfschema/pfs.cc:1862

#17 0x00007fe3cd3c74a4 in start_thread (arg=0x7fe3c5a25700) at pthread_create.c:456

#18 0x00007fe3cb90fd0f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97