This appears to be the same or similar issue as this, though it is not fixed.

I had noticed it intermittently over the last week.

On a refresh of the Newest Questions page, questions that were there are gone, only older ones appear. Several refreshes later all is well in the world.

This just happened again - some questions were marked "3 minutes ago", a refresh and they are gone and I am only seeing "6 minutes ago", even though there are newer questions.