I think it always did save on schedule, but it used to be unobtrusive. Now it flexes its muscles and momentarily "freezes" whatever Premiere is doing while it does its stuff.
I have also found that you need to have Date/time Modified shown in the file details in thye folder window to be sure which is your latest autosave since the default Date column shows the creation of the first backup file whith a particular name, and these names are re-used as time passes of course.
I'd consider auto-saving during certain operations (like playback) a bug---or at least worthy of a feature request.
I know that we just fixed a bug like this in After Effects where auto-save would kick you out of a text-editing operation.
Premiere only executes an autosave when there
are unsaved changes in the open program.
Save before you start playback of a timeline that is longer
than your autosave interval, and it will not be interrupted.
I have never experienced Pr kicking me out of an operation
when performing an autosave... yet.