But you could continue working and only have to apply minor patches forward if you later find your starting point needed to be fixed.
You don't have to wait for CI, just create a new branch and continue your work as though CI passed, and your PR was accepted. If that comes true you don't need to worry much, just rebase and continue.
On the other hand if you find out you needed to make changes - do those on the branch you made those changes, and finish your PR/CI cycle. Then go to the new branch you continued work on and rebase, and continue.
You don't have to wait for CI, just create a new branch and continue your work as though CI passed, and your PR was accepted. If that comes true you don't need to worry much, just rebase and continue.
On the other hand if you find out you needed to make changes - do those on the branch you made those changes, and finish your PR/CI cycle. Then go to the new branch you continued work on and rebase, and continue.
Is there something I am missing?