The accurate way of checking the type of ads served by Adsense on your website is NOT by loading your webpage on your web browser. If you find your website serving irrelevant ads on your browsers, it might not be so.
Ads from Google have logarithms that take into account your location, via IP addresses.
There's a better way to check the type of ads served, as seen through your target audience eyes, who might not be living in the same region as you.
Just use a web browser renderer.
For example, I've loaded a URL to netrenderer. It returned me the screenshot, shown below:
The page was featuring an artbook review. And the artbook was about Beowulf, a computer generated movie. The ads on the sidebar featured ads selling 3D products and services. The ads on the top horizontal strip featured art products and services.
Here's a list of browser renderers you can use:
Web rendering services has more websites that feature browser renderers. If you feel you need more, check them out. Otherwise, the 4 in the list above are more than sufficient for checking the ads.