I recently imported about 500 photos to my LR catalog and as I was reviewing them (with the sort order set to capture time) photos I had imported years ago started showing up instead of the photos that were supposed to be there. After displaying the wrong photo for about 30secs the displayed photo switches to the correct one. Anyone know why this is happening?
Which version of Lightroom are you running?
As a first step, try updating to the current version 2015.10.