Kong is silently responding the message "The upstream server responded with 200" with status code 200 rather than actual json response body

Question

Using self hosted kong (v3.7.x) on ec2 instance with traditional(database) topology

No configuration tweaked as of now, everything is running on the default configuration.

Sometimes kong responds with the message "The upstream server responded with 200" with status code 200 rather than the actual response body from upstream.

Disk/CPU/memory usage for each kong instance is well within 10-20%. I couldn't find any document around this.