If you are using kwallet-pam to unlock your kwallet wallets *and* have a encryptfs home, the automatic unlocking probably stopped working for you with Plasma 5.18.4 and you are getting a "Wallet failed to get opened by PAM, error code is -9" in the system log.
kwallet-pam uses something called a salt file.
Before Plasma 5.18.4 the salt file was read (or created if not existing) in the "authenticate" step of pam. Now that happens on the "open_session" step of pam.
This is very important because on the open_session the encrypted home is already mounted while in the authenticate step it is not.
What that means is that before Plasma 5.18.4 there was a /home/youruser/.local/share/kwalletd/kdewallet.salt *outside* your encrypted home (that was created/read on the "authenticate" step).
Now with Plasma >= 5.18.4 the /home/youruser/.local/share/kwalletd/kdewallet.salt is created/read correctly inside your encrypted home like the rest of your files.
This is all nice for new users, but if you have an existing user, the kwallet auto unlocking will stop to work.
Because your wallet was salted with the file that was outside your encrypted home folder, now since kwallet-pam can no longer read that, it fails.
How to fix it?
* Reboot your system
* Login as root (or as a different user)
* See that there is a /home/youruser/.local/share/kwalletd/kdewallet.salt (FILE_A)
* Copy that file somewhere safe
* Now login as the youruser user
* If you have a /home/youruser/.local/share/kwalletd/kdewallet.salt copy it somewhere else safe too (you shouldn't need it but just in case)
* Copy the FILE_A you stashed somewhere safe to /home/youruser/.local/share/kwalletd/kdewallet.salt
* Reboot your system and now everything should work