Here is another thought.
Human Error? All it takes is someone to punch in the wrong degrees (and not many) and instead of hitting Ukraine it hits Poland. Are there any places in Ukraine along the same longitude that were worth hitting for Russia to cause major damage to the power grid?
If human error is the case you got to wonder how much trained military Russia has left.
Hopefully it doesn't start WW3 but rather forces Russia to rethink that it could and pull out of Ukraine.