The alternate session forming only incrementally removes PRs from the currently considered PR set. Even if a PR by a responsive peer is known, if it was removed due to not passing the majority checks earlier, it will never be used by our peers during this epoch. With that in mind, we should only use the most recent KEs with the lowest referenced PR counts when trying to form an alternate session, as the additional PRs from earlier KEs will never be reconsidered by that KE's identity.
The alternate session forming only incrementally removes PRs from the currently considered PR set. Even if a PR by a responsive peer is known, if it was removed due to not passing the majority checks earlier, it will never be used by our peers during this epoch. With that in mind, we should only use the most recent KEs with the lowest referenced PR counts when trying to form an alternate session, as the additional PRs from earlier KEs will never be reconsidered by that KE's identity.