CoCoA » CoCoA-5

I get a SEGV with the following input (no SEGV if the number of loop iters is 100).

use QQ[x,y];

D := 3;
nvars := NumIndets(CurrentRing);
S := support((1+sum(indets(CurrentRing)))^D);

define rndpoly(S)
  return sum([random(-5,5)*t | t in S]);
enddefine; -- rndpoly

for i := 1 to 1000 do
  L := [rndpoly(RandomSubset(S,4)) | j in 1..nvars];
  I := ideal(L);
  RGB := ReducedGBasis(I);
  if len(RGB) = nvars then continue; endif;
  foreach G in subsets(RGB,nvars) do
    if CommonDenom(G) = 1 and ideal(G) = I then println G; endif;
  endforeach;
endfor;