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

TestUpgradeControlPlane/EnsureHostedCluster

Extreme regression detected.
Fishers Exact probability of a regression: 100.00%.
Test pass rate dropped from 100.00% to 33.33%.

Sample (being evaluated) Release: 4.20
Start Time: 2025-08-27T00:00:00Z
End Time: 2025-09-03T16:00:00Z
Success Rate: 33.33%
Successes: 5
Failures: 10
Flakes: 0
Base (historical) Release: 4.19
Start Time: 2025-05-18T00:00:00Z
End Time: 2025-06-17T23:59:59Z
Success Rate: 100.00%
Successes: 52
Failures: 0
Flakes: 0

View the test details report for additional context.

Potentially multiple problems causing it, I'm not entirely sure, though they did all seem to start permafailing on the 29th.

Hits additional tests, seemingly in every run.

TestUpgradeControlPlane
TestUpgradeControlPlane/EnsureHostedCluster/EnsureReadOnlyRootFilesystemTmpDirMount
TestUpgradeControlPlane/EnsureHostedCluster/EnsureReadOnlyRootFilesystem

Probably not related to https://issues.redhat.com/browse/OCPBUGS-61142 as it's in a different job and started several days prior.

Filed by: dgoodwin@redhat.com