I would like to follow up on how-can-you-move-items-between-plex-libraries-without-losing-the-metadata
Updating section_locations is not enough (at least today), you have to update media_parts as well with something like :
UPDATE `media_parts`
SET `file`=
REPLACE(`file`,
'/Old_Volume_Name/',
'/NEW_Volume_Name/')
WHERE `file` like '%Old_Volume_Name%';