The problem is not that the Ukrainian government cannot manage fair elections during war time, the problem is that they have never won a fair election. They lost in 2010 and overthrew the government in the 2014 Euromaidan revolution. This naturally destroyed people's faith in the democratic process, demolishing turnout in those areas that won the 2010 election but weren't within rioting distance of the capital.
The problem is not that the Ukrainian government cannot manage fair elections during war time, the problem is that they have never won a fair election. They lost in 2010 and overthrew the government in the 2014 Euromaidan revolution. This naturally destroyed people's faith in the democratic process, demolishing turnout in those areas that won the 2010 election but weren't within rioting distance of the capital.