it's something that youtube does when trying to figure out if someone is using a hack to get views.
this is usually seen happen on big youtube channels when they get 301 views for like a whole day while actulally like 10,000 people had viewd it.
so when this happens, they keep your video at one number for a day or two so that they can get checked by the youtube employees for faults, and when they detect that there is no fault and you did really get these views, they will give them back to you as fast as possible. don't worry, you havent lost any views, just give it a few days.