Main limesurvey.org site allows registration with github, but when trying to access the bug tracker, login user and password is requestd.
As I registered with github, I don't know what password to enter...
As a result, after going back and forth and receiving errors that I am already signed in (from main site), it seems the only solution is to log out from main site, and on the login popup do the "Forgot login" and request a new password.