If I had to have a guess (and I will qualify that I am not a network engineer!) this behaviour may be caused by the way that the internet works.
A rough and ready lesson: information travels in small packets - when you click on a link, your computer sends a packet or two of information to the website's server, saying you want to see their page. In return, the website starts sending back a stream of packets that make up the information of the web page.
All well and good so far?
Well, what can happen, is that not all the packets make it. Some of them get lost. Somewhere. In the ether. But your computer knows it wants them, so it sits and waits for them.
And here is where my understanding gets a little spotty, and where someone more educated than I may be able to fill in the blanks. I'm pretty sure that if it's been waiting for a while, your computer is meant to let the site know that it has missed a packet, and that it wants it again. For some reason, this may be taking longer than it should.
When you click stop and reload, then it automatically asks for the packets again, so the stream starts again.
That may or may not all make sense...
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