It's not a glitch, it's perfectly normal. The amount of views a thread has gets updated on certain intervals. This way it puts less strain on the forums. For instance if it gets updates every 5 minutes it starts with 0 views, then 5 minutes later 75 views (75 people viewed it in those 5 minutes) etc. I don't know exactly the specific time limit, but it isn't that long.
It's not a glitch, it's perfectly normal and it was done intentional.