According to Wikipedia, Georgia has a significant part of its country occupied by Russia:
[...] territories occupied by Russia after the Russo-Georgian War in 2008. They consist of the regions of Abkhazia and the former South Ossetian Autonomous Oblast of Soviet Georgia
According to this article, Georgia's President, Giorgi Margvelashvili said that a referendum cannot be held because the country has occupied territories:
we should take into account the law on a referendum. It says that referendum must be held on the entire territory of the country. I, as the guarantee of country’s unity and national independence, am obliged to defend country’s sovereignty in the first place. In the times when 20% of our territories is occupied and when Russia has recognized occupied territories as independent states, it would give the occupant more legal argumentations.
Question: is there any country that held referendum(s) in spite of having occupied or disputed territories that prevented it from including all its citizens within the referendum?