This is a clone of issue OCPBUGS-60851. The following is the description of the original issue:
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(Feel free to update this bug's summary to be more specific.)
Component Readiness has found a potential regression in the following test:

[sig-arch][Feature:ClusterUpgrade] Cluster should remain functional during upgrade [Disruptive] [Serial]

Significant regression detected.
Fishers Exact probability of a regression: 100.00%.
Test pass rate dropped from 99.01% to 85.29%.

Sample (being evaluated) Release: 4.20
Start Time: 2025-08-18T00:00:00Z
End Time: 2025-08-25T12:00:00Z
Success Rate: 85.29%
Successes: 29
Failures: 5
Flakes: 0
Base (historical) Release: 4.17
Start Time: 2024-09-01T00:00:00Z
End Time: 2024-10-01T00:00:00Z
Success Rate: 99.01%
Successes: 100
Failures: 1
Flakes: 0

View the test details report for additional context.

Filed by: dgoodwin@redhat.com