"[{"name":"additional[text][9]","value":"\u10e1 \u10d3\u10d0\u10e1\u10d0\u10d1\u10e3\u10d7\u10d4\u10d1\u10d0 (Judgement process"},{"name":"additional[text][3]","value":"version"}]"
If our json contains something like this \u10d3\u10d0\u10e1\u10d0\u10d1\u10e3\u10d7\u10d4\u10d1\u10d0
we have UTF-8 unicode problem.
JSON_UNESCAPED_UNICODE
fixes this problem, so we can encode json like this
json_encode($request->field_data, JSON_UNESCAPED_UNICODE)