Let's try to summarize a bit.

- problem is related to big websites;
- not every big website is infected;
- coverage not necessarily should be low to see no ads (my coverage is 90+);
- I saw ads were shown on page like this : No ads - Ads - No No No No Ads - Ads (same) - No No ads - Half Ads (different)
It says to me, that this is not about crawler, because even if these were 3rd party ads, then why page was not filled by them all the time.
Also G. didn't say, that re-crawl required and meantime you will receive 3rd party ads only. It said re-crawl required to receive ads. Any ads.
Also almost a month passed since new policy was implemented. Obviously things should be better every day, since more pages supposedly should be re-crawled, but nothing good
happens.
So, I don't see any evidence, that this is about crawler. Pure assumptions.

Please add your observations and conclusions.