Proton Pass password manager follows the bad practice of keeping unencrypted usernames and passwords in the computer’s memory.

#CoSoSec

To make matters worse, this sensitive data is not wiped from the memory when the vault is locked post-login, making it susceptible to exfiltration by info-stealer malware or attackers with physical access to the target machine

Seems they promised this would be fixed BUT several updates later still no fix

https://restoreprivacy.com/proton-pass-retains-passwords-in-cleartext-form-in-memory