During bootstrapping we're running into the following scenario:

4 members: master 0, 1 and 2 (are full voting) and bootstrap (torn down/dead member) revision rollout causes 0 to restart and leaves you with 2/4 healthy, which means quorum-loss.

This causes apiserver unavailability during the installation and should be avoided.
    

4.17, 4.18 but is likely a longer standing issue

rarely    

    1.
    2.
    3.
    

apiserver should not return any errors