"Turn off the alarms everyone, this part of the building isn't on fire."
It takes more than a few data-points to declare a trend reversed, especially one this big. In the paper I believe you're referring to they even conclude:
> Despite the slowdown and thickening we report here, glacier flow still exceeds the velocities of the early 1990s, when the mass balance of the glacier was nearly in equilibrium, and continues to contribute to Greenland’s net ice mass loss. [1]