I have noticed this several times before, but this time actually paid attention all the way through, albeit forgot to increase the combat reporting all the way up to really see an answer to this...but here goes..
The Russian side often in the early going of the 41 Campaign begins filling up with strength 0 units...most of the time(90+%) these units relocate if an Axis unit moves beside them. Sometimes, however, they still stand and fight. The combat report shows they have 0 men, 0 guns, 0 afv..yet, they sometimes stand and fight? And, not only do they fight on these , admittedly rare occasions, but they cause casualties(also, not many, this last time was 32 men and 1 afv) But what I am wondering is, with 0 men, WHAT is killing the Axis men and afv? And how can a 0 strength unit stand and make a division waste 2-3 MPs to fight it, when it obviously is only a "paper" division still in the process of fleshing out?