There seem to a number of reasons for this, some of which are quite complicated to resolve. However, the problem is often to do with the cache the browser keeps of pages visited. Try clearing the cache to see if this fixes the problem.
In Chrome select the “Customize and Control Chrome” button. It’s normally the button top right with 3 horizontal lines. Click this then choose “Tools”, “Clear Browsing Data”. In the check list make sure “Cached images and files” is ticked. At the top choose “The last 4 weeks” option and click the button at the bottom that says “Clear Browsing Data”.
If the page still jumps choose the “beginning of time” option and try again.
Other browsers have controls that do the same thing.