Perhaps the update altered your edited configuration file /etc/java-8-oracle/security/java.security ? In this case you should edit it again.
Sometimes all seems OK, you are on the login page, you enter your agency, account number and password, but after pressing the login button nothing happens (you immediately return to the login page). This could mean that your account is blocked, and you have to go to the agency and talk to a manager. However, this could also mean a glitch. To rule out a glitch:
Close the login tab in your browser and clean the browser history, everything
Close your browser and make sure that it is closed (the command pgrep firefox should return nothing)
Remove the Java directory in your home folder: rm -rf ~/.java
Go to https://seg.bb.com.br/ and see the diagnostics
If all seems OK, proceed to your login page and login as usual
Attention: this removes your security clearance.
Is could be my imagination... But it seems that Banco do Brasil has some tensions with the Firefox password manager. Firefox can remember passwords. Then, when you navigate to the login page, Firefox pre-fills-in your remembered login name and password.
In case of Banco do Brasil, it is better to erase that pre-filled-in password, and enter manually.
This could be an illusion. Such illusions often arise when dealing with low quality computer systems.