I think I have figured out how to disable this 'feature' in case anyone else is using LastPass and has the same change. If you go into your site vault, click on a site (ATP in this case) and then click the pencil icon to edit the site... there is a checkbox at the bottom that says 'disable auto fill'. That seems to have been unchecked on all sites in some recent upgrade. Irritating to have to go in and change them all, especially for me as I have dozens of sites in there for work, but at least it seems to have solved the problem.
