MAZ trucks (which ZiKZ 605-R was based on) have quite unique rear suspension. Something similar to rocker-bogie suspension:
Sadly suspension on ZikZ is acting as if it had independent suspension. Movement of 3rd row wheels doesn't affect 4th row wheels and vice-versa. The rocker arm just bends instead of rotating on the middle axis.
Here is video comparing how suspension worked properly in Mudrunner and how it works in Snowrunner: