We have approximately 225 mailboxes hosted in Office 365 in a hybrid environment. I quite often see Microsoft initiating mailbox moves between databases. More often than not, the Move Request Status has a result of Failed and lingers there for a while. I'll go back and check every so often when I'm doing moves of my own and notice that mailboxes that had previously failed due to anywhere from 1 - 20 corrupted items have since been successfully moved.
My question is what is Microsoft doing do resolve the issue of corrupted items? Are they just increasing the bad item limit before reinitiating the moves in order to successfully move the mailboxes, or do they recover the items before or after the moves from backup, or perform repairs, or ... ?