Seems to me it's the fault of whoever isn't in control of the Ukraine military or some units of the Ukraine military. At this point, after the musical chairs at Army HQ in Kiev, it's hard to tell who can actually give the Army an order and expect to have it obeyed.
The Nazis are calling the shots. They kept a low profile after fuhrer was voted out. Now they learnt Zelensky is an empty suit and out of woodwork.