TraceRT may show the issue.
I used it once when PGMusic was slow, and found out that where my ISP routed me to get to PGMusic was rather weird and one hop was slowing everything down.

I'm guessing some relay on the internet is having an issue that affects only certain routes to PGMusic site.

Tracert example (from memory)
My ISP (Comcast) was routing me to Toronto, then to Chicago then on westward.
I'm about halfway between Chicago and Toronto and they routed me in the opposite direction first.
Maybe they had too at the time because of an issue between me and Chicago, but they could go to Toronto and get around it.

It's pretty amazing how well the internet does work, all things considered.
A Node goes down, system tries to self heal .. at least as well as it was programmed to try.

Next idea is use F12 key in most any browser, go to network tab, and reload the page.
That'll tell you if something from the actual page at PGMusic is the source of the problem (though again it could be some script the site is using that is loading slowly on your machine from somewhere else). But it may help track it down.

I do not work here, but the benefits are still awesome
Make your sound your own!