Ever since I upgraded to Aperture 3.5.1 (from 3.4.5) and to Mavericks 10.9.2 (from Mountain Lion 10.8.5), I’ve noticed a slight (3-5) second delay upon launch in Projects View: the key photos associated with each project are a little blurry and only become sharp after the delay is over.

Any idea as to what could be causing this delay?