Kubuntu 15.10 & ecryptfs & change password

[Igor Mironchik]

Hi folks,

I found, probably, strange bug... I had Kubuntu 15.10 with ecryptfs on
my $HOME directory. Once I decided to change password for my user. I
went to the System Settings and there changed password, rebooted... And
I couldn't login to my Kubuntu. I saw login screen, entered new
password, pressed Enter... Screen flashed and went back to login screen.
Password is correct, I could login in console mode...

Is it a known bug?