When IngressController is configured with the woldcard policy enabled, the routes are not able to be reused by other route until router is restarted.   

    4.15

    always

** Activate WildCard Policy at IngressController:
$ oc patch ingresscontroller default -n openshift-ingress-operator --type=merge -p '{"spec":{"routeAdmission":{"wildcardPolicy":"WildcardsAllowed"}}}'
ingresscontroller.operator.openshift.io/default patched

** Create Dummy app and 2 routes pointing to the same service: 
$ oc new-project http-wildcardNow using project "http-wildcard" on server "https://api.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com:6443"....

$ oc new-app httpd--> Found image 70bf92d (4 weeks old) in image stream "openshift/httpd" under tag "2.4-ubi8" for "httpd"

$ oc expose service httpd --name httpd-cm1route/httpd-cm1 exposed
$ oc expose service httpd --name httpd-cm2route/httpd-cm2 exposed

$ oc get routes
NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD
httpd-cm1 httpd-cm1-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com httpd 8080-tcp None
httpd-cm2 httpd-cm2-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com httpd 8080-tcp None
     
** Update the host, Swap the host at the routers:

$ oc patch route httpd-cm1 --type=merge -p '{"spec":{"host":"httpd-cm2-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com"}}'
route.route.openshift.io/httpd-cm1 patched

$ oc patch route httpd-cm2 --type=merge -p '{"spec":{"host":"httpd-cm1-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com"}}'
route.route.openshift.io/httpd-cm2 patched

$ oc get routes                     
NAME        HOST/PORT                                                                   PATH   SERVICES   PORT       TERMINATION   WILDCARD
httpd-cm1   httpd-cm2-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com          httpd      8080-tcp                 None
httpd-cm2   HostAlreadyClaimed                                                                 httpd      8080-tcp                 None

** Even deleting the routes:
$ oc delete route httpd-cm1           
route.route.openshift.io "httpd-cm1" deleted
$ oc delete route httpd-cm2
route.route.openshift.io "httpd-cm2" deleted

$ oc get routes
No resources found in http-wildcard namespace.

$ oc create -f httpd-cm2.yaml 
route.route.openshift.io/httpd-cm2 created

$ oc get routes                                                                                             
NAME        HOST/PORT            PATH   SERVICES   PORT       TERMINATION   WILDCARD
httpd-cm2   HostAlreadyClaimed          httpd      8080-tcp                 None

$ oc get routes -o json | jq -r '.items[] |.metadata.name,.spec.host,.status.ingress[].conditions[].message'
httpd-cm2
httpd-cm1-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com
route http-wildcard/httpd-cm1 has host httpd-cm1-http-wildcard.apps.shrocp4upi414sdn.lab.upshift.rdu2.redhat.com

    error HostAlreadyClaimed  reported 

host route updated