I scanned a large number of slides and imported them into LR. I then started changing file names to reflect the subject matter and also gave a title and caption to each. After I work for awhile doing this, LR starts getting confused and will have the two titles, but duplicate images, with one image being lost. If I leave LR open for awhile and do nothing (3 or 4 minutes), it seems to get straightened out. and will eventually have the correct title with the correct image and will restore the lost image. What's causing this problem. I don't work fast, so it's not speed.