MAYBE
Trs:
 {                c(y, x, f(z)) -> b(f(b(z, x)), z),
  f(b(b(a(), z), c(a(), x, y))) -> z,
   b(b(y, z), c(a(), a(), a())) -> f(c(z, y, z))}
 Comment:
  We consider a duplicating trs.
  FAIL:
   Open