Oh wow, maybe it needs a manual intervention because mine are still missing the unlockable button. I sent an email as well so will see.
Edit: Just got an answer from Rarible.
"Hello, Ephemere NFT
We sincerely apologize for the delay in our response. A combination of the media sensation and a wave of new users has created significant demand for NFT issuance platforms like Rarible. We are working through large amounts of support tickets. Of course, this is not an excuse but merely an explanation. The majority of issues users face comes from the complex nature of the Ethereum blockchain and the infrastructure involved.
We hope you understand and accept our apology.
There is currently a front-end issue affecting unlockable content for NFTs. This content is not lost. Some items have already been restored. The developer team is working hard on a universal solution.
Thank you for reporting your problems to us. Your feedback helps us improve Rarible for everyone.
We are sorry about the inconvenience this is causing you and ideally, this won’t happen again in the future. There are updates being made to the platform at a fairly consistent rate. With new updates, sometimes there are new bugs encountered and thankfully, this is only cosmetic.
So they are working on it