In addition to the RuZZians shelling their own men in the liberated nuclear power plant, blowing up their own gas pipelines and bombing their own bridge, they've been shelling their own men on the front lines mercilessly.
90,000 effectives equate to about ten divisions, which is a heck of a lot of soldiers to lose in a war of seven months. Add in support equipment (tanks, trucks, etc.) and this has been awfully expensive for Russia.
In addition to the RuZZians shelling their own men in the liberated nuclear power plant, blowing up their own gas pipelines and bombing their own bridge, they've been shelling their own men on the front lines mercilessly.