(Feel free to update this bug's summary to be more specific.)
Component Readiness has found a potential regression in the following test:

install should succeed: cluster bootstrap

Significant regression detected.
Fishers Exact probability of a regression: 100.00%.
Test pass rate dropped from 98.99% to 89.76%.

Sample (being evaluated) Release: 4.21
Start Time: 2025-12-01T00:00:00Z
End Time: 2025-12-08T04:00:00Z
Success Rate: 89.76%
Successes: 114
Failures: 13
Flakes: 0
Base (historical) Release: 4.18
Start Time: 2025-01-26T00:00:00Z
End Time: 2025-02-25T00:00:00Z
Success Rate: 98.99%
Successes: 293
Failures: 3
Flakes: 0

View the test details report for additional context.

{}Affects Version{}: 4.21.0-0.nightly-2025-12-04-154904 and later
{}Last Working Version{}: 4.21.0-0.nightly-2025-12-04-023306

—

Error Messages:

From installer logs (`.openshift_install.log`):
```
Failed to create ipaddresses.v1beta1.ipam.cluster.x-k8s.io:
conversion webhook for ipam.cluster.x-k8s.io/v1beta1, Kind=IPAddress failed:
Post "https://capi-webhook-service.openshift-cluster-api.svc:443/convert?timeout=30s":
service "capi-webhook-service" not found
```

From bootstrap journals (`bootstrap/journals/bootkube.log`):
```
Error: error rendering asset "Cluster API resources": error running Cluster API
actuator: failed to create resource ipaddresses.v1beta1.ipam.cluster.x-k8s.io:
conversion webhook failed: service "capi-webhook-service" not found
```

—
Suspicious PR: https://github.com/openshift/cluster-api/pull/243

Maybe we should move this bug to cluster-capi-controllers component, but before that, it is better to confirm here.