We have an endpoint with potentially large json. It only occurred recently with it stuck and not returning anything and crashing the client on timeout.

We are sure that there is pending data to be sent via res.status(200).json(data). Sometimes it gets stuck, sometimes it sends a response. However when we use other 2xx status code, we receive a response right away (faster in fact).

What can cause this? Any solutions?

Next: 12.1.6

Edit: Codebase is 2 years already and it only occurred just out of nowhere.