The windshield wiper sprayers don't work properly when it gets significantly below freezing. This is incredibly dangerous on highways where it snows and the roads are salted, allowing for the snow to be thrown up as mud. This ends up in the windshield wipers just spreading mud all over the windshield and reducing visibility to near 0. Having this occur while driving at lower highway speeds makes this incredibly dangerous. Having to pull over on the highway when it's snowing isn't great, especially when some mountain highways have concrete walls with no shoulder. Using fluid that is rated for below freezing also causes this to freeze, suggesting that it may be related to wind chill while traveling at speed. It's also definitely not an issue with the overall system or the fluid because the rear windshield wipers still work. This is probably due to the way they designed this to move the emitters off the hood. A search for the term, "mazda cx-9 windshield wiper frozen", shows many such reports online. Some have complained to Mazda only to have this ignored by them. There were on indicators in the vehicle to show that that was a potential problem.
NHTSA ODI 11644015