If it was the same thing I was reading, it was that people assume end to end encyrpted password managers are fully safe because even if they get hacked the hackers can't get your passwords because of the encryption.
In reality, the passwords are decrypted within their ecosystem. Even if it's on your device, a vulnerability in the client could leak your password because you type your password into their client.
This is the same reason most (all?) E2E encryption is not a replacement for trusting the company. If Facebook wants the contents of your E2E encrypted chat, your app or browser is already decrypting them on your device. They can just change their app to capture the decrypted chat messages and send them to the NSA.