The "sponsored" ads at the bottom of the page are making 4chan tabs load eternally. They used to be archive exclusive but now appear in all blue boards and /pol/.
More specifically, the problem is caused by the web-sockets they use or that are somehow associated with and that keep making upgrade requests (what are they even for?). These are the conflicting urls (pic related)
wss://a.ekansovi.com/wsm
wss://a.ufraton.com/wsm
xhr.ekansovi.com
What really bugs me is that this also happens on /qa/ despite it has no ads. What are you pulling here? It's precisely because this kind of shady shit that people worry about getting datamined.