auto save not working right

blender is usually awesome for recovering from crashes, as i’ve got it set to auto save every 2 minutes.

today however i’ve been having a fair amount of trouble where the last auto save is always time stamped to the last time i actually saved. if my last save state was 5 minutes ago, the auto save is also from 5 minutes ago. if the last save was 30 minutes ago, so is the last auto save.

does anyone know what might have started this behaviour? i’m on 2.5a on OS X yosemite