Gröbner walk changes ideal, returns no Gröbner Basis

[ren]

The following problem arose when Tommy and I tried to compute a point on the tropical Grassmannian (the complete script is attached):

                     SINGULAR                                 /  Development
 A Computer Algebra System for Polynomial Computations       /   version 4.0.3
                                                           0<
 by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann     \   Jan 2016
FB Mathematik der Universitaet, D-67653 Kaiserslautern        \
> LIB "rwalk.lib";
> intvec w = [...];          // strictly positive weight vector
> ring r = 0,(...),(a(w),lp);
> ideal I = [...];           // homogeneous ideal
> int radius = 1;            // not sure what these two parameters are for
> int perturb_deg = 2;       // documentation claims they are optional, they are not
> ideal stdI = rwalk(I,radius,perturb_deg); 
> reduce(I,stdI);            // not 0
> ideal stdstdI = std(stdI); // does not terminate

[Christian Eder]

Bug is fixed with git commit 5c2efd6c794c0238c981879360698bbba3d9b2d7