2+2 is literally the only site this happens on that I wouldn't expect it to. If I were to go some questionable website like a torrent site or something, I'd expect to see these types of ads.
The fact that numerous people have had this happen probably means it isn't anyone's ISP. I'm not getting ISP related ads, either. It's one of those spam ads like "your computer has been infected" or "call Microsoft immediately about whatever".
I'm 99.9% certain it has to do with 2+2's ad network especially given the fact that there have been incidents in the past with other issues. I haven't seen anything for days, and no one has posted about it happening in awhile. I'm guessing whatever infected ad was in the network was removed, but I'll be sure to post a screenshot if it happens again.
But yes, keep saying it's an ISP when there is a history of this happening to big websites.
https://arstechnica.com/security/201...to-ransomware/