- Fixed a situation when, sometimes, the scheduler incorrectly placed a pod in the `unschedulable` queue instead of the `backoff` queue. This happened when some plugin previously declared the pod as `unschedulable` and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the `active`...

rejected via `UnschedulableAndUnresolvable`. Consequently, these nodes are excluded from the candidates for the preemption process. Additionally, this update corrects how the scheduling framework handles the Unschedulable status from PreFilter. Previously, if PreFilter returned `Unschedulable`, it could lead to an unexpected abortion in the preemption process, which shouldn't occur in the default scheduler but might occur in schedulers with custom plugins. ([#119779](https://github.com/kubernetes...

- Improved Node's QueueingHint in the `NodeAffinity` plugin by ignoring unrelated changes that keep pods unschedulable. ([#127444](https://github.com/kubernetes/kubernetes/pull/127444), [@dom4ha](https://github.com/dom4ha)) [SIG Scheduling and Testing]

  Previously, when unschedulable Pods are updated, the scheduler always put Pods back to activeQ/backoffQ. But, actually not all updates to Pods make Pods schedulable, especially considering many scheduling constraints nowadays are immutable.

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active"...

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active"...

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active"...

- The calculations for Pod topology spread skew now exclude nodes that
  don't match the node affinity/selector. This may lead to unschedulable pods if you previously had pods
  matching the spreading selector on those excluded nodes (not matching the node affinity/selector),

- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active"...

- DRA: the explanation for why a pod which wasn't using ResourceClaims was unscheduleable included a useless "no new claims to deallocate" when it was unscheduleable for some other reasons. ([#129823](https://github.com/kubernetes/kubernetes/pull/129823), [@googs1025](https://github.com/googs1025)) [SIG Node and Scheduling]