Frozen view count

YouTube video views reflect how many times a video has been watched and can be an important measure of a video's overall popularity.
On some videos, the view count might seem frozen or not show all the views that you expect. Video views are algorithmically validated to maintain fair and positive experiences for content creators, advertisers, and users. To verify that views are real and accurate, YouTube may temporarily slow down, freeze, or adjust the view count, as well as discard low-quality playbacks.

How views are counted
We want to make sure that videos are being viewed by actual humans and not computer programs. During the first couple of hours after a video has been published, we'll only show views that our systems believe to be valid. This might not yet show all legitimate views at that time.
After quality views are counted, view count updates more frequently. The process of including all quality views can take some time depending on a video's popularity and viewership. Afterward, the view count updates more frequently, but keep in mind that we're constantly validating views, so view count can always be adjusted.

Check views with YouTube Analytics
If you're looking at a video you uploaded, you can monitor your views more closely using YouTube Analytics. However, keep in mind that the Realtime report only shows estimates of potential view activity and might not match the number you see on the watch page.