For traditional Jenkins project types, Build or Build with Parameters pages redirect to the job index page upon submission, since there is no way of knowing how long it will be before the build starts—in general, it will wait in the queue for an executor. In some cases the queue might immediately schedule the build, but often it will not.

For Pipeline, newly scheduled Run items (as opposed to node blocks) are almost always scheduled immediately, since they merely need a flyweight executor slot on the master node, and there should not be anything stopping them from running. (Plugins can delay or cancel the build using various APIs. The only case I can think of offhand is jenkins.branch.RateLimitBranchProperty.QueueTaskDispatcherImpl.)

For better usability, we would expect the redirect to go straight to the build page if indeed the build can be scheduled immediately. I suspect this is most easily done in core, even if the biggest benefit is for Pipeline.

Should also be applied to Replay (or Rebuild) on Pipeline builds.