I have noticed that foo_audioscrobbler doesn't scrobble from RAM-Disk (foo_ramdisk). I don't know which of these two plugins have this bug, but it's exists.
you've probably got foo_audioscrobbler set to
only submit tracks from the media library. the console would confirm this...
Audioscrobbler: Track is not in Media Library - not submitting to Audioscrobbler.
you can change the setting under file>preferences>tools>audioscrobbler.
edit: i've confirmed this by testing it myself. it works from ramdisk when you turn that option off.
Thank you! I didn't think about this.