Why does Freesync fail so much?

I have a Sapphire Fury Tri-X graphics card connected to my LG UM67 29UM67 Ultrawide monitor via Display Port. AMD’s radeon settings app shows Freesync as on, I have frame limiting set to 74fps (Freesync caps out on this monitor at 75) and the AMD Freesync Windmill demo application clearly shows Freesync working when activated.

Yet too many times I load up a game and have to turn vsync on in order to not get tearing. Like today I bought Talos Principle and the tearing was insane at 60fps (capped via the game, cause AMD’s frame limiter didn’t take effect). I also had crazy tearing on Bioshock Infinite and Skyrim, both of which I had to turn vsync on to get rid of it (which defeats the point from my understanding, and the windmill demo app clearly shows vsync adding jitter). I’ve had tearing in a lot of other games that I’m forgetting off the top of my head.

What gives?

I have a Gsync monitor, not Freesync, but I know I have a setting as to whether it affects Windowed, fullscreen, or both types of applications. Does Freesync have anything similar? Maybe games running in fullscreen windowed mode aren’t working or something?