PATCH method dies with mod security with nginx configured as proxy/ingress

Version info:

version: libmodsecurity.so.3.0.3

name: nginx-ingress
repository: https://kubernetes-charts.storage.googleapis.com
version: 1.33.5
kubectl version
Server Version: version.Info{Major:"1", Minor:"16", GitVersion:"v1.16.9", GitCommit:"a17149e1a189050796ced469dbd78d380f2ed5ef", GitTreeState:"clean", BuildDate:"2020-04-16T23:15:50Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"linux/amd64"}

===> cross-post from https://github.com/kubernetes/ingress-nginx/issues/5723

Summary Observations:
PATCH method with JSON request body sent to ingress receives no response bytes on connection and connection is left open.

Connection is closed only when NGINX ingress is bounced due to server reload (on change of ConfigMap, pod deletion ... etc)

when Debug logging is enabled with
SecDebugLog /dev/stdout
SecDebugLogLevel 4

the debug log shows that phase 1 of the Modsecurity (a) recognized the "application/json", and that (b) phase 2 assigned the JSON attributes into ARGS for subsequent scanning.

** Changing from "DetectOnly" to rule enforcement does not change the behavior. Adding the CRS ruleset does not change the behavior.

** POST and PUT methods work without hanging the connection
** PATCH method works correctly when enable-modsecurity: "false"

====================================

Reproduce a PATCH request with an application/json body through the nginx-ingress path using the listed ModSecurity and Kubernetes versions. Enable SecDebugLog /dev/stdout and SecDebugLogLevel 4, then compare the ModSecurity phases with POST and PUT; done means PATCH returns a response and does not leave the connection open.