Windswept savannas sometimes generate in cold locations it shouldn't generate. In the screenshot, this savanna was in the middle of a windswept hill, forest and swamp with no savanna in sight. The area according to the F3 screen is very cold with temperature being in the negative. Overall, the windswept savanna in the screenshot is an odd place for it to be and should be a windswept hills instead.

It appears only windswept savannas can generate in factor 0.625 terrain, despite the temperature. Probably because no biomes is configured to generate there and windswept savannas happens to fill in most of the criteria (low factor and possibly other noise values allowing it to generate there despite cold).

Reproduce

Seed: -9212050702945381572
Coords: -11756 156 7226