If you do anything you want secure in a web browser (such as logging into your bank account), you probably want to avoid enabling extensions that can "Read and change all your data on all websites" like ad blockers. Or at least disable them while logging in. This is regardless of whether the browser is in Incognito or non-Incognito modes. A helpful extension that doesn't look at your data and disables all other extensions with a button push (when pinned to the address bar) is "Disable Extensions and Apps"