Hey guys!
After a terrible experiment with relocation of my custom nas (into a closed closet), my synology got f*ed up (volumes went missing ++, blank UIs etc).
So I decided to update to the latest version - prepared to setup all my disks over again, starting fresh.
I downloaded the latest june loader (1.04b) and booted up my NAS. To my surprise, a migration option appeared when visiting find.synology.com.
I ran migration and now everything is up and running, with no errors. All my disks and volumes is back to normal.
Operation success.
Big cred to this awesome community!