Adblock seems to work but not all the time and I don't even know where to start to figure out what could be happening.
This is where I first noticed it.
I can refresh the page and sometimes the ads are blocked and sometimes not. I know the ads are blacklisted.
It could be a browser cache problem, as the ads are likely sourced from several servers.
Note that Adblock is DNS based and knows nothing of the contents. It only prevents address resolution. If the ad is already in browser cache or the DNS resolution in the PC's routing cache, the ad may get shown.
Clear browser cache, reboot router and the PC. Also try with another browser.