Simulation hangs when sampling sets of type face.

I have an LES of a half open channel (empty atmospheric boundary layer). The domain is a cuboid. The mesh is built with blockMesh, without grading, and the cells are nearly uniform. I use the pimpleFoam solver. I'm using openfoam v2012.

I'm trying to sample on a line in my domain, running from one side to the opposing side, somewhere though the middle of my domain and parallel with one of the coordinate axes. I'm using sets from libsampling.so. I'm trying to use the type face, which should sample at intersections of the specified line and mesh cell faces. As my mesh cells are evenly spaced, this is very convenient.

I've noticed that my simulation sometimes hangs and sometimes not. By hanging I mean, that the log file from calling pimpleFoam > log is created, and that the simulation doesn't stop, but simply gets stuck at a certain line in the log file. E.g. during the last simulation where I had this problem, the simulation stopped at the line containing "outlet":

Creating finite volume options from "constant/fvOptions"

No finite volume options present
Courant Number mean: 0.001365 max: 0.0013832
fieldAverage fieldAverage1:
    Restarting averaging for fields:
        U: starting averaging at time 0

turbulenceFields turbulenceFields1: storing fields:
    turbulenceProperties:R

Reading set description:
    buildings
    inlet
    outlet

I've furthermore noticed that when I adjust one of the coordinates of the line, then the simulation sometimes doesn't hang anymore and sometimes it still hangs.

This seems like a bug in the sampling application.