explain format = ‘verbose’ has different behavior with explain format=‘VERBOSE’

[AilinKid]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required

USE test;
DROP TABLE IF EXISTS t;
CREATE TABLE t (id int, dc datetime, cc1 char(20), cc2 char(20));
INSERT INTO t VALUES (1, '2022-05-01 15:33:33', 'UUtJeaV', 'snRXXCZHBPW'), (2, '2022-05-01 15:33:33', 'snRXXCZHBPW', 'UUtJeaV');

explain format = 'verbose' select id, DAYNAME(dc), MONTHNAME(dc) from t;
explain format='VERBOSE' select id, DAYNAME(dc), MONTHNAME(dc) from t;

2. What did you expect to see? (Required)

the result should be the same

3. What did you see instead (Required)

the CAPITAL one shows
TiDB-v6> explain format='VERBOSE' select id, DAYNAME(dc), MONTHNAME(dc) from t;
ERROR 1105 (HY000): runtime error: index out of range [0] with length 0

4. What is your TiDB version? (Required)

master