The size extent of the GEOTREE2 leaves is given relative to the local smoothing length, it is not allowed to be smaller than GEOTREE2_BND_FinalBoxDimension * (local SMOOTH_LENGTH).
In this case, the size extent is bounded by abs(GEOTREE2_BND_FinalBoxDimension) * USER_h_min instead of the local smoothing length.
Warning: Make sure that USER_h_min is properly set when using the advanced option!
Note:
See also GEOTREE2_BND_FinalBoxSize. The first criterion, that is triggered, is used for the search-tree-construction.
Make sure to never set this parameter to GEOTREE2_BND_FinalBoxDimension = 0. This is reserved for debugging and can lead to unexpected behavior.