Steps to reproduce:
(1) Start any portal instance and tell the browser to store the password for firstname.lastname@example.org.
(2) Create a new database (anything which requires password) and set it up in the portal-ext.properties. The database password should be different from what's stored in the browser for email@example.com
(3) Start DXP
(4) On the Basic Configuration screen click Finish
What will happen is that on a non-visible field the password for the database is replaced with the admin user's password so it won't be able to connect.