I've observed that downloading an article from the AMP viewer doesn't really work -- it says "downloading" for a few minutes without making progress and eventually adds something to downloads home with no title and a size of -1B.

You can repro this by searching in the Google Search app or in Chrome's omnibox and opening a news story from the carousel. I'm using Chrome dev 58.0.3019.3.

(Tal sending to you for triage -- is this a KI?)