It's incredibly frustrating that autosaves won't occur if a manual save has been done. From working with many video and animation programs, saving often is important because of how unreliable they can be. Which makes it incredinly frustrating when they are and you lose your file.
It's then made worse by the autosave function not triggering because you've tried to be careful, my autosave is set at 5 miniutes, and it's resulted in me losing 2 hours of work. It really should just trigger even with manual saves, it would then make it easier to have longer periods between autosaves