I have uploaded images from multiple cameras and some files have identical times, which is causing LR 5.7 to get confused as to which thumbnail to show me. It can actually change while I'm clicked on a particular image. I cannot figure out how to fix this issue. Any suggestions?
Do those files with the identical times have the exact same file name as well?
You may have to rebuild your previews. Close Lightroom. Go to the folder where you LR catalog is located, delete the subfolder whose name ends with Previews.LRDATA. Do not delete anything else.
The files should be different, but the thumbnails keep changing for about a dozen files as I'm viewing the contact sheet in LR.