Readiness probes for router are failing with "No ref for container" on OpenShift Container Platform 3

Issue

• Readiness probe for router is failing once in a while with the below error message. It only is failing once and the following check is again successful meaning there is no restart or similar triggered. Still we'd like to understand why this is happening and why we are seeing No ref for container when this issue is happening.

Jul 06 15:26:34 node.example.com atomic-openshift-node[8313]: W0706 15:26:34.200801    8313 prober.go:103] No ref for container "docker://a572168853266b01558abd857eecfd4f25aebd810d1bb34c18d663f20340185d" (router-10-zm4wv_default(75726112-69d9-4c22-9901-f3902f50465a):router)
Jul 06 15:26:34 node.example.com atomic-openshift-node[8313]: I0706 15:26:34.200842    8313 prober.go:111] Readiness probe for "router-10-zm4wv_default(75726112-69d9-4c22-9901-f3902f50465a):router" failed (failure): Get http://localhost:1936/healthz/ready: net/http: request canceled (Client.Timeout exceeded while awaiting headers)

• After updating the image of our routers to 3.11.232, we constantly get not ready messages in our events.

LAST SEEN   FIRST SEEN   COUNT     NAME                               KIND      SUBOBJECT                 TYPE      REASON      SOURCE                                      MESSAGE
26m         1d           247       router-15-fjm6j.161f9d10ef66cc82   Pod       spec.containers{router}   Warning   Unhealthy   kubelet, node.example.com   Readiness probe failed: Get http://localhost:1936/healthz/ready: net/http: request canceled (Client.Timeout exceeded while awaiting headers)