Assertion `to_len >= 8' failed in convert_to_printable

SET optimizer_trace = 'enabled=on';

CREATE TABLE t1 ( a blob, KEY (a(255)));

DELETE FROM t1 WHERE a = REPEAT('a',0);

DROP TABLE t1;

#3  <signal handler called>

#4  0x00007fa6e273f428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54

#5  0x00007fa6e274102a in __GI_abort () at abort.c:89

#6  0x00007fa6e2737bd7 in __assert_fail_base (fmt=<optimized out>, assertion=assertion@entry=0x55da62a254d0 "to_len >= 8", file=file@entry=0x55da62a25300 "/10.4/sql/sql_string.cc", line=line@entry=1154, function=function@entry=0x55da62a25820 <convert_to_printable(char*, unsigned long, char const*, unsigned long, charset_info_st const*, unsigned long)::__PRETTY_FUNCTION__> "uint convert_to_printable(char*, size_t, const char*, size_t, CHARSET_INFO*, size_t)") at assert.c:92

#7  0x00007fa6e2737c82 in __GI___assert_fail (assertion=0x55da62a254d0 "to_len >= 8", file=0x55da62a25300 "/10.4/sql/sql_string.cc", line=1154, function=0x55da62a25820 <convert_to_printable(char*, unsigned long, char const*, unsigned long, charset_info_st const*, unsigned long)::__PRETTY_FUNCTION__> "uint convert_to_printable(char*, size_t, const char*, size_t, CHARSET_INFO*, size_t)") at assert.c:101

#8  0x000055da61ec69f3 in convert_to_printable (to=0x7fa6dc2ba7ee "", to_len=4, from=0x0, from_len=0, from_cs=0x55da634c3a40 <my_charset_bin>, nbytes=0) at /10.4/sql/sql_string.cc:1154

#9  0x000055da61ec6c06 in String::append_semi_hex (this=0x7fa6dc2ba7d0, s=0x0, len=0, cs=0x55da634c3a40 <my_charset_bin>) at /10.4/sql/sql_string.cc:1210

#10 0x000055da6211ed32 in Field::print_key_value_binary (this=0x7fa6c0138df0, out=0x7fa6dc2ba7d0, key=0x0, length=0) at /10.4/sql/field.cc:11267

#11 0x000055da6211ecc5 in Field_blob::print_key_value (this=0x7fa6c0138df0, out=0x7fa6dc2ba7d0, length=255) at /10.4/sql/field.cc:11258

#12 0x000055da622c7a4a in print_key_value (out=0x7fa6dc2baf00, key_part=0x7fa6c0138fd8, key=0x7fa6c00667b1 "", used_length=258) at /10.4/sql/opt_range.cc:15861

#13 0x000055da622c74bf in print_range (out=0x7fa6dc2baf00, key_part=0x7fa6c0138fd8, range=0x7fa6dc2ba990, n_key_parts=1) at /10.4/sql/opt_range.cc:15745

#14 0x000055da622c7789 in trace_ranges (range_trace=0x7fa6dc2bb0b0, param=0x7fa6dc2bb360, idx=0, keypart=0x7fa6c0066b48, key_parts=0x7fa6c0138fd8) at /10.4/sql/opt_range.cc:15804

#15 0x000055da622b2569 in get_key_scans_params (param=0x7fa6dc2bb360, tree=0x7fa6c00669c0, index_read_must_be_used=false, update_tbl_stats=true, read_time=4.3000000000000007) at /10.4/sql/opt_range.cc:7386

#16 0x000055da622a70ee in SQL_SELECT::test_quick_select (this=0x7fa6c0014090, thd=0x7fa6c0000b00, keys_to_use=..., prev_tables=0, limit=18446744073709551615, force_quick_range=false, ordered_output=false, remove_false_parts_of_where=false, only_single_index_range_scan=false) at /10.4/sql/opt_range.cc:2895

#17 0x000055da61f077e4 in SQL_SELECT::check_quick (this=0x7fa6c0014090, thd=0x7fa6c0000b00, force_quick_range=false, limit=18446744073709551615) at /10.4/sql/opt_range.h:1653

#18 0x000055da622eec1f in mysql_delete (thd=0x7fa6c0000b00, table_list=0x7fa6c0013220, conds=0x7fa6c0013c00, order_list=0x7fa6c00054b0, limit=18446744073709551615, options=0, result=0x0) at /10.4/sql/sql_delete.cc:546

#19 0x000055da61dfbc63 in mysql_execute_command (thd=0x7fa6c0000b00) at /10.4/sql/sql_parse.cc:4727

#20 0x000055da61e06d4a in mysql_parse (thd=0x7fa6c0000b00, rawbuf=0x7fa6c0013128 "DELETE FROM t1 WHERE a = REPEAT('a',0)", length=38, parser_state=0x7fa6dc2bcff0, is_com_multi=false, is_next_command=false) at /10.4/sql/sql_parse.cc:7908

#21 0x000055da61df2fb8 in dispatch_command (command=COM_QUERY, thd=0x7fa6c0000b00, packet=0x7fa6c0008331 "DELETE FROM t1 WHERE a = REPEAT('a',0)", packet_length=38, is_com_multi=false, is_next_command=false) at /10.4/sql/sql_parse.cc:1843

#22 0x000055da61df16d2 in do_command (thd=0x7fa6c0000b00) at /10.4/sql/sql_parse.cc:1360

#23 0x000055da61f6c076 in do_handle_one_connection (connect=0x55da64c71c20) at /10.4/sql/sql_connect.cc:1404

#24 0x000055da61f6bd9f in handle_one_connection (arg=0x55da64c71c20) at /10.4/sql/sql_connect.cc:1306

#25 0x000055da62897cdf in pfs_spawn_thread (arg=0x55da64b96bd0) at /10.4/storage/perfschema/pfs.cc:1862

#26 0x00007fa6e35806ba in start_thread (arg=0x7fa6dc2be700) at pthread_create.c:333

#27 0x00007fa6e281141d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109