Try adding a new reminder on the same list from the phone. See if it A: Adds that new reminder to the list on the Mac. B: Refreshes your list and the item from the Mac you are waiting for shows up on the phone.
This is a problem I've been having. Anything I add FROM my Mac doesn't make it too my phone. But things added from my phone not only make it too my Mac but update the things previously added from the Mac onto the phone.
My only solution that seems to work pretty consistently is move from iCloud to Google. Unfortunately I don't think Google has reminders, just Calendar, Notes, Mail and Contacts.
About twenty minutes before I started typing this post I used my Mac to edit my reminders, probably been a total of 30 minutes now still with no change on any of my iOS devices. I could tell they weren't syncing properly anyway because they were all different some more out dated then others.