I haven't seen these for several updates but they're back now, and apparently with a vengeance. Started popping up again after my phone updated MMA to b1076.
"Creating new video thumbnails"

. I do not use MMA for videos. None are synced from MMW, it is not set to be my video player, and there are no video file folders in its configured library location.
"Scanning folders to the library"

. I do not add content from outside the MMA/MMW sync pairing; all database and library management is done through the desktop sync there are no new folders to scan once the sync has finished cleaning up.
There should be nothing happening at all to trigger either of these as nothing is happening from outside of MMA to its database or library files. And yet these two background tasks pop up very very frequently.