Since JBoss EAP for OpenShift uses "recreate" for its template's DeploymentConfig strategy by default, all the sessions will disappear when you deploy a new app version.
https://github.com/jboss-container-images/jboss-eap-7-openshift-image/blob/7.3.x/templates/eap73-openjdk11-https-s2i.json#L526

This is neither same as the default DeploymentConfig strategy (Rolling), nor same as standard (non on OpenShift) JBoss EAP behavior. (When a new war file is deployed to a standard JBoss EAP, sessions are kept).

I think this surprising and unexpected behavior (from customer's view point) should be documented somewhere in the getting started guide.
( "3.7. Deployment Considerations for the JBoss EAP for OpenShift Image" might be a good candidate. https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.3/html/getting_started_with_jboss_eap_for_openshift_container_platform/configuring_eap_openshift_image#deployment_considerations_for_eap_openshift_image)