iPhone photos database corruption

I keep several folders on my computer synced through iTunes to my phone (Vacation 2012, Vacation 2013, Vacation 2014, etc...) but every few days the folders get messed up. My phone still shows all of the folders but the pictures are not in the correct folders. Sometimes it even shows the same folder multiple times containing different pictures. If I physically connect my phone to my computer and sync to remove the pictures and then re-sync to add the folders back then everything is fixed... for a few days and then it corrupts again. This has happened across multiple phones (two different iPhone 5 and one iPhone 6). Ideas?