An erasure coded pool with "4+2" chunks created on a ruleset with four OSD nodes, ends up moving the cluster status to HEALTH_WARN, why?

Issue

• An EC pool created with "4 + 2" chunks on a ruleset mapped to four OSD nodes, shifts the cluster from being HEALTH_OK to HEALTH_WARN.

• A 'ceph -s' shows:

# ceph -s
cluster <cluster-id>
     health HEALTH_WARN
            600 pgs degraded
            600 pgs stuck degraded
            600 pgs stuck unclean
            600 pgs stuck undersized
            600 pgs undersized
     monmap e1: 3 mons at {mon1:6789/0,mon2:6789/0,mon3:6789/0}
            election epoch 6, quorum 0,1,2 mon1,mon2,mon3
     osdmap e361: 81 osds: 81 up, 81 in; 600 remapped pgs
      pgmap v1083: 864 pgs, 3 pools, 533 MB data, 181 objects
            5156 MB used, 61124 GB / 61129 GB avail
                 600 active+undersized+degraded+remapped
                 264 active+clean