Rancher cordones nodes one by one when new node added to cluster/rancher

Hi, currently doing some maintenance works on k8s controlplane nodes (etcd, masters) and noticed that when new node is deleted and then added, rancher ui all nodes one by one are reporting “cordoned” state for few seconds.

Maybe some reference in docs, github, etc. Just want to understand what is then happening, maybe this is not rancher related, from my limited knowledge it is not clear why it should be done.

Was wondering why is that? ( v2.6.13 if it makes difference)