This sometimes happens to me when I follow the "View Bill Details" link and click "Print/Save Statement (PDF)". When that doesn't work I go to the "View Bill History" link on the main Billing page, and click the "View PDF" link for the current bill on https://customer.xfinity.com/#/billing/past-statements. That usually works, but sometimes I just have to wait a day or two until Billing gets its act together and fixes the links.
I've been having the same problem for several days now. I even cleaned cache today thinking that might be the problem, but didn't work. Can't get PDF copy to appear.
I just tried your suggestion of using past bills link. I saw the bill date there, but still no luck when I click it. Guess I'll give it another few days.
Verified print/save current statement just now still broken for me too on current bill details screen. 0 byte PDF file. But viewing via "previous statements" is working for me, tho.
This had started working again for me, I just got the correct full not-zero-byte bill PDF when clicking print/save statement on the bill details screen. Time will tell if it stays working now. This is the second time in 5 years that this basic paperless bill delivery function has publicly broken on this website, not good for something branded as "EcoBill".