The environment uses nginx php-fpm, and the data requested by post are sent in data=json format, but the json format data in some requests is missing.
{
"items": "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
Where should I start when this happens?
Try using php://input to receive data?
Use other tools (wireshark...) to check the http request and make sure the data is complete?