Missing Allies on Rift Map

Here are all the details I have:

1. I can not see any summoner icons on the minimap or the allies themselves on the screen.
2. I could see enemies icons on the minimap and enemies on the screen.
3. I could see at least some ally effects (e.g. Ashe's big arrow and scout trails) on the big map but NOT the minimap.
4. I was playing Brand. My allies seemed to not be affected by this lack of vision.
5. This effect happened well into the game (20 minutes or so).
6. I do not yet know if it is repeatable. If it is I will edit this post. (I certainly hope not - It's a scary world out on the rift with invisible friends).
7. I could not see any ally pings. (I am assuming they pinged at least once in the last 5-10 minutes of the game.)