This is quite interesting. The first thing that comes to my mind is the clipboard sniffing. Copy/paste should be never used for passwords. Using it for master password is even more dangerous if you are using a cloud based password manager. KeePass(XC) has Auto-Type after all.

I also wonder if these cases with 1Password and Bitwarden are related: https://old.reddit.com/r/1Password/comments/rimvc8/constantl... https://old.reddit.com/r/Bitwarden/comments/rmp1c4/what_is_t...