bug in primdecGTZ over prime field

[kroeker@…]

Here is the failing input example:

system("random",1397912804);

LIB("primdec.lib");
LIB("ehv.lib");

ring rng = 7,(x,y,z),dp;
ideal I = -y3+2x2-1,-z3,-x2y-1;

int count = 0;
def L1 = primdecGTZ(I);
def L2 = primdecGTZ(I);
L1;
L2;
ASSUME(0, primDecsAreEquivalent(L1, L2) );  //fails for given seed

$;

the entries L1[1][2] and L[2][2] are not prime:

//L1;
[1]
   [1]
      _[1]=z3
      _[2]=y4+y+2
      _[3]=y3+3y2+x-1
   [2]
      _[1]=z3
      _[2]=y4+y+2
      _[3]=y3+3y2+x-1
[2]
   [1]
      _[1]=z3
      _[2]=y4+y+2
      _[3]=-y3-3y2+x+1
   [2]
      _[1]=z3
      _[2]=y4+y+2
      _[3]=-y3-3y2+x+1

//L2:
[1]
   [1]
      _[1]=z3
      _[2]=y4+y+2
      _[3]=y3+3y2+x-1
   [2]
      _[1]=z
      _[2]=y4+y+2
      _[3]=y3+3y2+x-1
[2]
   [1]
      _[1]=z3
      _[2]=y4+y+2
      _[3]=-y3-3y2+x+1
   [2]
      _[1]=z
      _[2]=y4+y+2
      _[3]=-y3-3y2+x+1