DistanceOctree<MeshType>::writeVTKOutput(..) might take very long to complete

I create and output a DistanceOctree as is indicated in Tutorial - LBM 4: Complex Geometry.

Using a mesh with 110k vertices, running my code on the Emmy cluster and writing the VTK-output to $FASTTMP I noticed that the runtime of DistanceOctree<MeshType>::writeVTKOutput(..) can drastically vary from run to run. Anything between 5 minutes and 5 hours has been observed.