Hi Tadas,
Can you help me to test this with you on your system? I tried testing on BetaSprings but I can't change Dynamic Login there to be based on email sign in ( i.e. module configuration>Allow user to login with their email address
It is only set up for username sign in. I would think you can change it on your site cause you are set up for email sign in right now. Can you make two test users with username: UserA and UserB? You can do this from admin>user accounts. To do the test make their password something like UserApass01, and UserBpass02. Make each have your email so they both have same email and you will be the one to receive the email the system for password information. Then go to host>scheduler and fire the scheduler to update these new users. Start out with both Authorized and login with your email. Now the question is what username and password do you get in your email inbox? Try it again with one of them set to Unauthorized and do the test again. Does the email that comes to your in box have information for the authorized username and password only? Can you make the email info change to the other user if you set him to authorized and the other to unauthorized? Hopefully we see that only the authorized user gets the email from email login.
If your results are not satisfying then the one way to force things where you have two users with the same email is to base the login in Dynamic Login on the username and password and not email.
I hope to hear back from you on this. In the meantime I will look for more information to update you
Thanks