2 factor authentication fails on GitLab.com

GitLab.com is running 7.12.0.rc1-ee cd29cff3 .

User with enabled 2FA cannot login, error is:

worker1 production.log: Completed 500 Internal Server Error in 39ms
worker1 production.log: 
worker1 production.log: OpenSSL::Cipher::CipherError (bad decrypt):
worker1 production.log:   app/controllers/sessions_controller.rb:95:in `valid_otp_attempt?'
worker1 production.log:   app/controllers/sessions_controller.rb:63:in `authenticate_with_two_factor'
worker1 production.log: 

@dzaporozhets @rspeicher Any ideas?

Also in https://dev.gitlab.org/gitlab/gitlabhq/issues/2405