You have a mobile friendly web site according to Google, you pass all the tests, but your new content isn't showing the mobile-friendly label until much later after you post the news story - why?
For example, I posted a story on Friday and it showed "3 hours ago" label instead of the "mobile friendly" label in the mobile search results on Friday:
After the story was no longer considered "fresh" and maybe "new," Google removed the x hours ago label and placed the "mobile friendly" label in the search results. Here is a picture:
The question is, is the delay in showing the mobile friendly label related to Google first needing to figure out if the page is mobile friendly or because Google has only space to show X hours ago OR mobile friendly and thus picks X hours ago over the mobile friendly label in the search results.
In seems like it is a space issue, because when I asked Gary Illyes from Google about this and I asked if this is an issue with the site appearing not to be mobile friendly, he said no.
@rustybrick no
— Gary Illyes (@methode) April 17, 2015
So I suspect Google will pick up new pages as mobile friendly virtually as soon as they pick up the new page but it may not show the mobile friendly label until later only because it rather show the X hours/minutes ago label.
Forum discussion at Twitter.