Cells with high-value of velocity
 

Hi, I've computed a potentialFoam and got a strange result. In a few number of cells the velocity value is too high (>0.8 m/s). The normal velocity value ranges in [0; 0.5]. The screenshot is attached.

Maybe someone know the reason of this issue and how to fix it ?
Maybe I need to change some parameter in snappyHexMeshDict or change a fvScheme ?

The project file is here: https://yadi.sk/d/1PZZCoagsPbTL