As I understand it the secrets are on a shared lock out but I don't actually fully understand how it works. Does it work like all other boss loot i.e once a boss is dead you don't get another chance for a secret from that boss. For example say I kill durumu in LFR and no secret drops will I still have a chance at a secret from durumu normal?
Or is it that receiving a secret from a boss THEN locks the other difficulties of said boss for that week?