Troubleshooting may necessitate enabling logging of JSessionID and VCAP_ID to make sure these headers are being received by Gorouter.
These headers are necessary for Gorouter to guarantee session affinity / stickiness.
See HTTP routing for more information.
JESSIONID and VCAP_ID headers, add "Set-Cookie, Cookie" to the "HTTP Headers to Log" field in the OpsManager > PAS/TAS > Networking tab. JSESSIONID and the __VCAP_ID__ will now show up on the Gorouter access logs and we can confirm if Gorouter is not adhering to the sticky session.