Why doesn't my Ceph cluster fully redistribute PGs after an OSD is marked down and out?

Issue

• Why doesn't my Ceph cluster fully redistribute PGs after an OSD is marked down and out?
• When an OSD goes offline or is marked down and out, it's been observed that most of the PGs/objects will redistribute appropriately to other OSDs but there are occasionally some Placement Groups (PGs) that remain "stuck" and/or degraded until the OSD is manually removed from the OSD map.