Chrome 69 was released to users on September 5th, 2018. Besides the different look and feel one other annoying change is that Chrome now logs you automatically into Google services like Gmail with the same account that you use for browser syncing. Previously, users were allowed to keep those logins separate. To disable the forced login, navigate to chrome://flags/#account-consistency. Then set the option labeled,
Identity consistency between browser and cookie jar to
Disabled and restart your browser.