JSON_TABLE returns an empty value for a valid Unicode escape and ignores ERROR ON ERROR

I get an empty non-NULL value from JSON_TABLE when valid latin1 JSON contains the Unicode escape \u0424 and the output column uses utf8mb4. The same value is decoded as Ф (UTF-8 hex D0A4) by JSON_UNQUOTE, while JSON_TABLE also reports warning 4035 despite ERROR ON ERROR.

This occurs when JSON_TABLE projects a Unicode escape from latin1 JSON into an utf8mb4 column.

The following equivalent SQL reproduces the issue; the JSON_TABLE alias is incidental:

SET NAMES utf8mb4;

SELECT JSON_UNQUOTE(CONVERT('"\\u0424"' USING latin1)) AS unquote_control,

       HEX(JSON_UNQUOTE(CONVERT('"\\u0424"' USING latin1))) AS control_hex,

       JSON_VALID(CONVERT('["\\u0424"]' USING latin1)) AS valid_json;

SELECT x, HEX(x) AS extracted_hex

FROM JSON_TABLE(

       CONVERT('["\\u0424"]' USING latin1),

       '$[*]' COLUMNS(x VARCHAR(10) CHARACTER SET utf8mb4 PATH '$' ERROR ON ERROR)

     ) AS jt;

SHOW WARNINGS;

The recorded output was:

unquote_control  control_hex  valid_json

Ф                D0A4         1

x  extracted_hex

Level    Code  Message

Warning  4035  Broken JSON string in argument 0 to function 'st_append_json' at position 0

JSON_VALID confirms that the input is valid, and JSON_UNQUOTE demonstrates that \u0424 decodes to Ф with UTF-8 hex D0A4. JSON_TABLE should therefore return Ф and D0A4 for the utf8mb4 output column without a broken-JSON warning. If conversion were to fail, ERROR ON ERROR should not silently produce an empty value.