Sometimes 1 or 2 or 3 locs unknown to you can break off and fall out. You probably won't know why they fell out. And, you may not even find the departed loc. The reason for the locs falling out could be due to tight hairstyles that pull, a diet that lacks minerals required for good hair growth and of course stress can be a cause of hair loss (both past and present). And last but not least retightening too tightly or just natural wastage. You can feel bad and shocked...and then spend the following days searching for the lost loc and wondering what you did wrong or you can run through the possible factors for breakage, assess, remedy and then move on. The reality is that hair can break even when locked. The important question is how much has broken?