Wrong string lenght?

[Hugo]

When i want to send JSON formated topic via mqtt, i have to add space to end of the string

{"device_class":"temperature","name":"Temperature","state_topic":"homeassistant/sensor/m5core_01/state","unit_of_measurement":"°C","value_template":"{{value_json.temperature}}"}
without space on the end missing right curly brace and is not possible to parse.

[m5stack]

@hugo could you provide you whole block screenshot and python code? what UIFlow version are you used？