For http_proxy instead of https_proxy cluster, it needs not trigger proxy config check when configmaps change.

4.14.0-0.nightly-2023-07-31-181848

Always

1. Successfully launch a 4.14 http_proxy cluster using Installer QE's Jenkins installer job with installer template ipi-on-aws/versioned-installer-customer_vpc-http_proxy-ci. The proxy is shown as below:
$ oc get proxy cluster -o yaml
...
spec:
  httpProxy: http://<user>:<password>@ec2-xx-xx-xx-xx.us-east-2.compute.amazonaws.com:3128
  httpsProxy: http://<user>:<password>@ec2-xx-xx-xx-xx.us-east-2.compute.amazonaws.com:3128
  noProxy: test.no-proxy.com
  trustedCA:
    name: ""
status:
  httpProxy: http://<user>:<password>@ec2-xx-xx-xx-xx.us-east-2.compute.amazonaws.com:3128
  httpsProxy: http://<user>:<password>@ec2-xx-xx-xx-xx.us-east-2.compute.amazonaws.com:3128
  noProxy: .cluster.local,.svc,.us-east-2.compute.internal,10.0.0.0/16,10.128.0.0/14,127.0.0.1,169.254.169.254,172.30.0.0/16,api-int.<cluster-name>.qe.devcluster.openshift.com,localhost

2. Manually oc edit proxy cluster to add the oauth route to noProxy:
...
spec:
  ...
  noProxy: test.no-proxy.com,oauth-openshift.apps.<cluster-name>.qe.devcluster.openshift.com
...

3. Wait 15 mins for cluster components to roll out.

4. In a terminal A, watch proxy server's logs:
# tail -f /var/log/squid/access.log | grep 'CONNECT oauth-openshift.apps.<cluster-name>.qe.devcluster.openshift.com'

In another terminal B, run:
$ date; oc label cm/trusted-ca-bundle -n openshift-authentication-operator test6=abcd
Tue Aug  1 09:50:41 UTC 2023 
configmap/trusted-ca-bundle labeled
$ date; oc label cm/default-ingress-cert -n openshift-config-managed test7=abcd
Tue Aug  1 09:51:07 UTC 2023
configmap/default-ingress-cert labeled

In step 4 terminal A, the `tail -f` command shows:
# tail -f /srv/squid/log/access.log | grep 'CONNECT oauth-openshift.apps.<cluster-name>.qe.devcluster.openshift.com'
1690883448.918      6 10.0.52.212 TCP_TUNNEL/200 3379 CONNECT oauth-openshift.apps.<cluster-name>.qe.devcluster.openshift.com:443 <proxy user> HIER_DIRECT/18.219.206.4 -
1690883473.147     10 10.0.52.212 TCP_TUNNEL/200 3379 CONNECT oauth-openshift.apps.<cluster-name>.qe.devcluster.openshift.com:443 <proxy user> HIER_DIRECT/18.219.206.4 -


Convert the timestamps:
# date --date=@1690883448.918
Tue Aug  1 09:50:48 UTC 2023
# date --date=@1690883473.147
Tue Aug  1 09:51:13 UTC 2023

They are immediately after the timestamps of terminal B. That is, terminal B's configmaps changes trigger the proxy config check.

However, the proxy `httpsProxy: http://<user>:<password>@ec2-xx-xx-xx-xx.us-east-2.compute.amazonaws.com:3128` is http instead of https, and the proxy's trustedCA name is blank. For such http proxy instead of https proxy, certificates are not cared about. So, the proxy config check should ingore the related certificate CAs configmaps' change to be less obtrusive.