This issue has only occurred in the last week--up to this point I have had no problems between Gmail and Outlook. However, as of last week, SOME of my Gmail comes into Outlook, and some does not--I only discovered this when people kept asking me why I hadn't responded and I went directly to my Gmail account online.
There is no rhyme or reason--the same person can gmail me on the same day, and some will show up while others will not.