Not even a glitch this is likely caching by design. The same thing happens here on a2k. If we write to the database on every thread view there is potential for a bottleneck as two writes can't happen concurrently (at exactly the same time) and one will be delayed.
Most of the time this is not a problem as it can handle many per second, but with enough traffic the view counter becomes a single bottleneck. The way to solve it is to cache that value, and have a background process count up the views and update it.
Here on a2k, the views will sometimes be out of sync if the background process dies, but usually gets done within a minute. Try it for yourself, start a thread and see how long the views are reported to be "0" even though you've viewed it yourself.
In youtube's case it seems at least hours off sometimes.