I've set up fscrypt home directory encryption on Ubuntu 18.04 following guide by @tlbdk.

Then I've tried to access my Ubuntu system using ssh public key authentication. Logically ssh server refuses to authorize using public key and forces ssh client to ask user for a password. However in contrast to pam_ecryptfs/pam_mount solutions password is still required for following simultaneous login attempts when home directory has been unlocked.

Having to say if ssh server is restarted after home directory has been unlocked -- public key authentication works.