Azure Container Instance: Very slow inbound network interface readiness on linux container.

Question

Since some weeks we are experiencing really, really slow network readiness on our Linux container on ACI (inbound only, outbound works almost immediately).
Really slow means that most times it takes about 5 minutes or longer until the container is reachable.

I deleted the Container Group and re-created it afterwards but this does not change it. This also happens almost every time the container group is started.

I have read about Windows containers having that problem, but nothing about Linux containers. (https://learn.microsoft.com/en-us/azure/container-instances/container-instances-troubleshooting#windows-containers-slow-network-readiness)

I am using a linux container image with debian 10 and a predefined nonroot user (gcr.io/distroless/cc-debian10:nonroot) and copy a Linux executable built by the Unreal Engine. The executable starts really fast and almost immediately sends an HTTP request to a backend of mine. But other Unreal clients that are trying to connect to the server simply get a connection timeout and need to retry for about 5 Minutes.

Any ideas how to workaround that? This also does not seem to be a known issue to Microsoft, since I cannot find any ticket or documentation on it.

Best
Stephen