For LO accounts that are connected through sync to an offline database, if the LO records has a bad email status (hard bounce, etc.), when a new email has been entered in the offline database, and syncs into the records updating the email field, the email status field in LO should be automatically resetting itself to a status of "Unknown" so new email can be put into circulation.

I assumed this was logically how things have been working all of this time, but recently tested it to find that it was not the case sadly.